Research

20 pages, 1715 KiB

Open AccessArticle

Predicting the Responses of Functional Leaf Traits to Global Warming: An In Situ Temperature Manipulation Design Using Iris pumila L.

by Sanja Manitašević Jovanović, Katarina Hočevar, Ana Vuleta and Branka Tucić

Plants 2023, 12(17), 3114; https://doi.org/10.3390/plants12173114 - 30 Aug 2023

Cited by 1 | Viewed by 975

Abstract

Phenotypic plasticity is widely acknowledged as one of the most common solutions for coping with novel environmental conditions following climate change. However, it is less known whether the current amounts of trait plasticity, which is sufficient for matching with the contemporary climate, will [...] Read more.

Phenotypic plasticity is widely acknowledged as one of the most common solutions for coping with novel environmental conditions following climate change. However, it is less known whether the current amounts of trait plasticity, which is sufficient for matching with the contemporary climate, will be adequate when global temperatures exceed historical levels. We addressed this issue by exploring the responses of functional and structural leaf traits in Iris pumila clonal individuals to experimentally increased temperatures (~1.5 °C) using an open top chamber (OTC) design. We determined the phenotypic values of the specific leaf area, leaf dry matter content, specific leaf water content, and leaf thickness in the leaves sampled from the same clone inside and outside of the OTC deployed on it, over seasons and years within two natural populations. We analyzed the data using a repeated multivariate analysis of variance, which primarily focusses on the profiles (reaction norms (RNs)) of a variable gathered from the same individual at several different time points. We found that the mean RNs of all analyzed traits were parallel regardless of experienced temperatures, but differed in the level and the shape. The populations RNs were similar as well. As the amount of plasticity in the analyzed leaf trait was adequate for coping with elevated temperatures inside the OTCs, we predict that it will be also sufficient for responding to increased temperatures if they exceed the 1.5 °C target. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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15 pages, 2527 KiB

Open AccessArticle

Acquisition of Freezing Tolerance of Resurrection Species from Gesneriaceae, a Comparative Study

by Gergana Mihailova, Bekim Gashi, Nikola Krastev and Katya Georgieva

Plants 2023, 12(9), 1893; https://doi.org/10.3390/plants12091893 - 05 May 2023

Cited by 3 | Viewed by 1216

Abstract

Resurrection plants have the unique ability to restore normal physiological activity after desiccation to an air-dry state. In addition to their desiccation tolerance, some of them, such as Haberlea rhodopensis and Ramonda myconi, are also freezing-tolerant species, as they survive subzero temperatures [...] Read more.

Resurrection plants have the unique ability to restore normal physiological activity after desiccation to an air-dry state. In addition to their desiccation tolerance, some of them, such as Haberlea rhodopensis and Ramonda myconi, are also freezing-tolerant species, as they survive subzero temperatures during winter. Here, we compared the response of the photosynthetic apparatus of two other Gesneriaceae species, Ramonda serbica and Ramonda nathaliae, together with H. rhodopensis, to cold and freezing temperatures. The role of some protective proteins in freezing tolerance was also investigated. The water content of leaves was not affected during cold acclimation but exposure of plants to −10 °C induced dehydration of plants. Freezing stress strongly reduced the quantum yield of PSII photochemistry (Y(II)) and stomatal conductance (g_s) on the abaxial leaf side. In addition, the decreased ratio of F_v/F_m suggested photoinhibition or sustained quenching. Freezing-induced desiccation resulted in the inhibition of PSII activity, which was accompanied by increased thermal energy dissipation. In addition, an increase of dehydrins and ELIPs was detected, but the protein pattern differed between species. During recovery, the protein abundance decreased and plants completely recovered their photosynthetic activity. Thus, our results showed that R. serbica, R. nathaliae, and H. rhodopensis survive freezing stress due to some resurrection-linked traits and confirmed their freezing tolerance. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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17 pages, 1257 KiB

Open AccessFeature PaperArticle

Garlic Ecotypes Utilise Different Morphological, Physiological and Biochemical Mechanisms to Cope with Drought Stress

by Ivanka Habuš Jerčić, Anita Bošnjak Mihovilović, Ana Matković Stanković, Boris Lazarević, Smiljana Goreta Ban, Dean Ban, Nikola Major, Ivana Tomaz, Zrinka Banjavčić and Snježana Kereša

Plants 2023, 12(9), 1824; https://doi.org/10.3390/plants12091824 - 28 Apr 2023

Cited by 4 | Viewed by 1243

Abstract

Drought negatively affects plants by altering morphological, physiological and metabolic processes and ultimately reducing yields. Garlic (Allium sativum L.), an important member of the Alliaceae family, is also sensitive to drought and maximizing the yield of garlic bulbs is largely dependent on [...] Read more.

Drought negatively affects plants by altering morphological, physiological and metabolic processes and ultimately reducing yields. Garlic (Allium sativum L.), an important member of the Alliaceae family, is also sensitive to drought and maximizing the yield of garlic bulbs is largely dependent on water availability. The objective of this study was to determine the effects of drought stress on morphological and physiological characteristics, as well as on phenolic, sugar, inulin and free amino acid content and antioxidant activity in two Croatian garlic ecotypes, ‘Istarski crveni’ (IC) and Istarski bijeli (IB). Drought was induced by using polyethylene glycol 8000 (PEG) solution (−0.6 MPa) starting 21 days after clove planting and lasted for 20 days. Drought reduced plant height, number of leaves and plant weight, but increased root length in both ecotypes compared to the control treatment. Among the physiological parameters, significant differences were observed between the two ecotypes studied in the spectral characteristics of the leaves, namely reflection in red, green and blue, VAL, values of the vegetation indices related to the chlorophyll content (CHI, GI), and the anthocyanin content (ARI). Ecotype IC showed higher antioxidant activity in the control treatment due to higher total phenolic content (TPC), but under drought conditions higher DPPH radical scavenging activity was determined in ecotype IB and higher values of FRAP in IC. Sucrose and glucose generally decreased under drought, while inulin increased in IB but decreased in IC. Total free amino acid content increased under drought in both ecotypes. In conclusion, drought tolerance of IB might be associated with increased accumulation of inulin and higher levels of amino acids, especially those shown to contribute to drought resistance. In IC, drought tolerance is associated with an increase in some amino acid compounds and better root growth in depth, probably due to a more efficient translocation of sucrose to the underground part of the plant. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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23 pages, 19009 KiB

Open AccessArticle

Potential Role of Biochar and Silicon in Improving Physio-Biochemical and Yield Characteristics of Borage Plants under Different Irrigation Regimes

by Saad Farouk, Arwa Abdulkreem AL-Huqail and Seham M. A. El-Gamal

Plants 2023, 12(8), 1605; https://doi.org/10.3390/plants12081605 - 10 Apr 2023

Cited by 7 | Viewed by 1524

Abstract

Silicon (Si) and biochar (Bc) are key signaling conditioners that improve plant metabolic processes and promote drought tolerance. However, the specific role of their integrative application under water restrictions on economical plants is not yet well understood. Two field experiments throughout 2018/2019 and [...] Read more.

Silicon (Si) and biochar (Bc) are key signaling conditioners that improve plant metabolic processes and promote drought tolerance. However, the specific role of their integrative application under water restrictions on economical plants is not yet well understood. Two field experiments throughout 2018/2019 and 2019/2020 were conducted to examine the physio-biochemical modifications and yield attributes of borage plants mediated by Bc (9.52 tons ha⁻¹) and/or Si (300 mg L⁻¹) under different irrigation regimes (100, 75, and 50% of crop evapotranspiration). Catalase (CAT) and peroxidase (POD) activity; relative water content, water, and osmotic potential; leaf area per plant and yield attributes; and chlorophyll (Chl) content, Chl_a/chlorophyllide_a (Chlid_a), and Chl_b/Chlid_b were considerably reduced within the drought condition. On the other hand, oxidative biomarkers, as well as organic and antioxidant solutes, were increased under drought, associated with membrane dysfunction, superoxide dismutase (SOD) activation, and osmotic adjustment (OA) capacity as well as a hyperaccumulation of porphyrin intermediates. Supplementation of Bc and Si lessens the detrimental impacts of drought on several plant metabolic processes associated with increasing leaf area and yield attributes. Their application under normal or drought conditions significantly elicited the accumulation of organic and antioxidant solutes as well as the activation of antioxidant enzymes, followed by lessening the formation of free radical oxygen and mitigating oxidative injuries. Moreover, their application maintained water status and OA capacity. Si and/or Bc treatment reduced protoporphyrin, magnesium-protoporphyrin, and protochlorophyllide while increasing Chl_a and Chl_b assimilation and boosting the ratio of Chl_a/Chlid_a and Chl_b/Chlid_b, resulting in a rise in leaf area per plant and yield components following these modifications. These findings highlight the significance of Si and/or Bc as (a) stress-signaling molecule(s) in regulating defensive systems in drought-affected borage plants by boosting antioxidant aptitude, regulating water status, and accelerating chlorophyll assimilation, thus leading to increasing leaf area and productivity. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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24 pages, 9948 KiB

Open AccessArticle

The Protective Effect of Exogenous Ascorbic Acid on Photosystem Inhibition of Tomato Seedlings Induced by Salt Stress

by Xianjun Chen, Hongwei Han, Yundan Cong, Xuezhen Li, Wenbo Zhang, Wenliang Wan, Jinxia Cui, Wei Xu, Ming Diao and Huiying Liu

Plants 2023, 12(6), 1379; https://doi.org/10.3390/plants12061379 - 20 Mar 2023

Cited by 4 | Viewed by 1588

Abstract

This study investigated the protective effects of exogenous ascorbic acid (AsA, 0.5 mmol·L⁻¹) treatment on salt-induced photosystem inhibition in tomato seedlings under salt stress (NaCl, 100 mmol·L⁻¹) conditions with and without the AsA inhibitor lycorine. Salt stress reduced the [...] Read more.

This study investigated the protective effects of exogenous ascorbic acid (AsA, 0.5 mmol·L⁻¹) treatment on salt-induced photosystem inhibition in tomato seedlings under salt stress (NaCl, 100 mmol·L⁻¹) conditions with and without the AsA inhibitor lycorine. Salt stress reduced the activities of photosystem II (PSII) and PSI. AsA treatment mitigated inhibition of the maximal photochemical efficiency of PSII (F_v/F_m), maximal P700 changes (P_m), the effective quantum yields of PSII and I [Y(II) and Y(I)], and non-photochemical quenching coefficient (NPQ) values under salt stress conditions both with and without lycorine. Moreover, AsA restored the balance of excitation energy between two photosystems (β/α-1) after disruption by salt stress, with or without lycorine. Treatment of the leaves of salt-stressed plants with AsA with or without lycorine increased the proportion of electron flux for photosynthetic carbon reduction [Je(PCR)] while decreasing the O₂-dependent alternative electron flux [Ja(O₂-dependent)]. AsA with or without lycorine further resulted in increases in the quantum yield of cyclic electron flow (CEF) around PSI [Y(CEF)] while increasing the expression of antioxidant and AsA–GSH cycle-related genes and elevating the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG). Similarly, AsA treatment significantly decreased the levels of reactive oxygen species [superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂)] in these plants. Together, these data indicate that AsA can alleviate salt-stress-induced inhibition of PSII and PSI in tomato seedlings by restoring the excitation energy balance between the photosystems, regulating the dissipation of excess light energy by CEF and NPQ, increasing photosynthetic electron flux, and enhancing the scavenging of reactive oxygen species, thereby enabling plants to better tolerate salt stress. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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14 pages, 2624 KiB

Open AccessArticle

Response of Juvenile Saccharina japonica to the Combined Stressors of Elevated pCO₂ and Excess Copper

by Wenze Zhang, Lianghua He, Jiangqi Pan, Yuhong Zhou, Ruxiang Ge, Sufang Li, Yunyun Shi, Xinhua Chen and Yaoyao Chu

Plants 2023, 12(5), 1140; https://doi.org/10.3390/plants12051140 - 02 Mar 2023

Cited by 1 | Viewed by 1106

Abstract

Coastal macroalgae may be subjected to global and local environmental stressors, such as ocean acidification and heavy-metal pollution. We investigated the growth, photosynthetic characteristics, and biochemical compositions of juvenile sporophytes of Saccharina japonica cultivated at two pCO₂ levels (400 and 1000 ppmv) [...] Read more.

Coastal macroalgae may be subjected to global and local environmental stressors, such as ocean acidification and heavy-metal pollution. We investigated the growth, photosynthetic characteristics, and biochemical compositions of juvenile sporophytes of Saccharina japonica cultivated at two pCO₂ levels (400 and 1000 ppmv) and four copper concentrations (natural seawater, control; 0.2 μM, low level; 0.5 μM, medium level; and 1 μM, high level) to better understand how macroalgae respond to ongoing environmental changes. The results showed that the responses of juvenile S. japonica to copper concentrations depended on the pCO₂ level. Under the 400 ppmv condition, medium and high copper concentrations significantly decreased the relative growth rate (RGR) and non-photochemical quenching (NPQ) but increased the relative electron transfer rate (rETR) and chlorophyll a (Chl a), chlorophyll c (Chl c), carotenoid (Car), and soluble carbohydrate contents. At 1000 ppmv, however, none of the parameters had significant differences between the different copper concentrations. Our data suggest that excess copper may inhibit the growth of juvenile sporophytes of S. japonica, but this negative effect could be alleviated by CO₂-induced ocean acidification. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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19 pages, 2101 KiB

Open AccessFeature PaperArticle

Transgressive Biochemical Response to Water Stress in Interspecific Eggplant Hybrids

by Sara González-Orenga, Mariola Plazas, Elvira Ribera, Claudia Pallotti, Monica Boscaiu, Jaime Prohens, Oscar Vicente and Ana Fita

Plants 2023, 12(1), 194; https://doi.org/10.3390/plants12010194 - 03 Jan 2023

Cited by 3 | Viewed by 1560

Abstract

In a climate change scenario, crop tolerance to drought must be urgently improved, as it represents an increasingly critical stress reducing agricultural yields worldwide. Although most crops are relatively sensitive to water stress, many of their wild relatives are more tolerant and may [...] Read more.

In a climate change scenario, crop tolerance to drought must be urgently improved, as it represents an increasingly critical stress reducing agricultural yields worldwide. Although most crops are relatively sensitive to water stress, many of their wild relatives are more tolerant and may be used to improve drought tolerance in our crops. In this study, the response to drought of eggplant (Solanum melongena), its close wild relatives S. insanum and S. incanum and their interspecific hybrids with S. melongena was assessed. The plants were subjected to two treatments for 18 days: control, with irrigation every four days, and drought, with complete interruption of irrigation. Morphological and biomass traits were measured, and physiological and biochemical responses were analysed using stress biomarkers such as proline, flavonoids, and total phenolic compounds. Oxidative stress was quantified by measuring malondialdehyde (MDA) content. As a result of the drought treatment, plant development and tissue water content were seriously affected. Generally, water deficit also caused significant increases in MDA, proline, flavonoids, and total phenolics compounds. Our results comparing parental accessions reveal a better response to drought in one of the S. insanum accessions. The hybrid between S. melongena and S. incanum displayed a better response than the other hybrids and even its parents. The results obtained here might be helpful for future eggplant breeding programmes aimed at improving drought tolerance. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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15 pages, 3907 KiB

Open AccessArticle

Salinity-Induced Physiological Changes in Pea (Pisum sativum L.): Germination Rate, Biomass Accumulation, Relative Water Content, Seedling Vigor and Salt Tolerance Index

by Mohammad Ayub Hossain Khan, Md. Abdul Baset Mia, Md. Abdul Quddus, Khokan Kumer Sarker, Mohibur Rahman, Milan Skalicky, Marian Brestic, Ahmed Gaber, Amnah Mohammed Alsuhaibani and Akbar Hossain

Plants 2022, 11(24), 3493; https://doi.org/10.3390/plants11243493 - 13 Dec 2022

Cited by 10 | Viewed by 2999

Abstract

Salinity affects and limits the yield potential of pulse crops. Therefore, an experiment was conducted to evaluate the salinity-induced physiological response of field peas by estimating the germination rate (%), accumulation of biomass, relative water content, and seedling vigor and salt tolerance index. [...] Read more.

Salinity affects and limits the yield potential of pulse crops. Therefore, an experiment was conducted to evaluate the salinity-induced physiological response of field peas by estimating the germination rate (%), accumulation of biomass, relative water content, and seedling vigor and salt tolerance index. The treatments included four salinity levels (NaCl) (i.e., 0 (control), 8, 12, and 16 dS m⁻¹, respectively) and eight field pea genotypes (i.e., BD4175, BD4182, BD4225, BD6944, BD4176, BD4193, BD4493, and BD4496). All treatments were arranged in a factorial completely randomized design and repeated four times. Results indicated that the percentage and rate of germination, percentage reduction of fresh and dry weight, relative water content, seedling vigor index, and salt tolerant index of all genotypes of field peas were influenced significantly by the different levels of salinity. The radicle and plumule of all field pea genotypes were damaged by applying 12 and 16 dS m⁻¹ salt stress. However, among these eight pea genotypes, two genotypes, namely BD4175 and BD4225, performed better under the 8 dS m⁻¹ level of salinity and these two genotypes may be recommended for cultivation in field conditions of saline coastal areas of Bangladesh, and can also be used in future breeding programs for the development of salt-tolerant pea cultivars. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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18 pages, 2805 KiB

Open AccessArticle

Photosynthetic Traits of Páramo Plants Subjected to Short-Term Warming in OTC Chambers

by María Elena Solarte, Yisela Solarte Erazo, Elizabeth Ramírez Cupacán, Camila Enríquez Paz, Luz Marina Melgarejo, Eloisa Lasso, Jaume Flexas and Javier Gulias

Plants 2022, 11(22), 3110; https://doi.org/10.3390/plants11223110 - 15 Nov 2022

Viewed by 1610

Abstract

Global warming and changes in land use are some of the main threats to high mountain species. Both can interact in ways not yet assessed. In this study, we evaluated the photosynthetic responses of six common páramo species within a warming experiment using [...] Read more.

Global warming and changes in land use are some of the main threats to high mountain species. Both can interact in ways not yet assessed. In this study, we evaluated the photosynthetic responses of six common páramo species within a warming experiment using open-top chambers (OTC) in conserved páramo areas with different land use histories. We did not find significant differences in the photochemical performance of the species as measured through Fv/Fm, ETR, and NPQ in response to passive warming, indicating that warmed plants are not stressed. However, NPQ values were higher in recovering areas, especially in the driest and warmest months. Leaf transpiration, stomatal conductance, and Ci were not affected by the OTC or the land use history. The photosynthetic capacity, maximum photosynthetic capacity, and carboxylation rate of RuBisCO increased in response to warming but only in the area with no anthropogenic intervention. These results suggest that species will respond differently to warming depending on the history of páramo use, and therefore not all páramo communities will respond equally to climate change. In disturbed sites with altered soil conditions, plants could have a lower breadth of physiological response to warming. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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17 pages, 4099 KiB

Open AccessEditor’s ChoiceArticle

Relative Water Content, Proline, and Antioxidant Enzymes in Leaves of Long Shelf-Life Tomatoes under Drought Stress and Rewatering

by Cristina Patanè, Salvatore L. Cosentino, Daniela Romano and Stefania Toscano

Plants 2022, 11(22), 3045; https://doi.org/10.3390/plants11223045 - 10 Nov 2022

Cited by 14 | Viewed by 3003

Abstract

Some physiological, oxidative, and antioxidant enzymatic patterns were assessed in plants of three local Sicilian landraces of long shelf-life tomatoes (‘Custonaci’, ‘Salina’, and ‘Vulcano’), as compared to the commercial tomato hybrid ‘Faino’ (control). Three water treatments were considered in open-field: DRY (no irrigation); [...] Read more.

Some physiological, oxidative, and antioxidant enzymatic patterns were assessed in plants of three local Sicilian landraces of long shelf-life tomatoes (‘Custonaci’, ‘Salina’, and ‘Vulcano’), as compared to the commercial tomato hybrid ‘Faino’ (control). Three water treatments were considered in open-field: DRY (no irrigation); IRR (long-season full irrigation); REW (drought/rewatering cycles). During the growing season, soil water deficit (SWD) was estimated, and relative water content (RWC), specific leaf area (SLA), proline and malondialdehyde (MDA) content, and glutathione peroxidase (GPX), catalase (CAT), and superoxide dismutase (SOD) activities were measured in leaves. Differently from control, RWC in local landraces exhibited a similar pattern in REW and DRY, indicating a low capacity to re-hydrate after rewatering. Positive correlation of proline content vs. SWD in all local landraces highlights an osmotic adjustment occurring in these tomatoes in response to limited soil water content. Long shelf-life tomatoes suffered minor oxidative stress due to severe soil water deficit, as revealed by the lower levels of MDA with respect to the control. Significant correlation of CAT vs. SWD for all tomatoes indicates that this antioxidant enzyme, among those analyzed, may be considered as a biomarker for a water stress condition more than for oxidative stress due to water deficit. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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13 pages, 1727 KiB

Open AccessArticle

Decreased Salinity Offsets the Stimulation of Elevated pCO₂ on Photosynthesis and Synergistically Inhibits the Growth of Juvenile Sporophyte of Saccharina japonica (Laminariaceae, Phaeophyta)

by Wenze Zhang, Yunyun Shi, Lianghua He, Xinhua Chen, Fengxiao Hu, Yinrong Chen, Yun Pang, Sufang Li and Yaoyao Chu

Plants 2022, 11(21), 2978; https://doi.org/10.3390/plants11212978 - 04 Nov 2022

Cited by 2 | Viewed by 1300

Abstract

The combined effect of elevated pCO₂ (Partial Pressure of Carbon Dioxide) and decreased salinity, which is mainly caused by freshwater input, on the growth and physiological traits of algae has been poorly assessed. In order to investigate their individual and interactive effects [...] Read more.

The combined effect of elevated pCO₂ (Partial Pressure of Carbon Dioxide) and decreased salinity, which is mainly caused by freshwater input, on the growth and physiological traits of algae has been poorly assessed. In order to investigate their individual and interactive effects on the development of commercially farmed algae, the juvenile sporophytes of Saccharina japonica were cultivated under different levels of salinity (30, 25 and 20 psu) and pCO₂ (400 and 1000 µatm). Individually, decreased salinity significantly reduced the growth rate and pigments of S. japonica, indicating that the alga was low-salinity stressed. The maximum quantum yield, F_v/F_m, declined at low salinities independent of pCO₂, suggesting that the hyposalinity showed the main effect. Unexpectedly, the higher pCO₂ enhanced the maximum relative electron transport rate (rETR_max) but decreased the growth rate, pigments and soluble carbohydrates contents. This implies a decoupling between the photosynthesis and growth of this alga, which may be linked to an energetic reallocation among the different metabolic processes. Interactively and previously untested, the decreased salinity offset the improvement of rETR_max and aggravated the declines of growth rate and pigment content caused by the elevated pCO₂. These behaviors could be associated with the additionally decreased pH that was induced by the low salinity. Our data, therefore, unveils that the decreased salinity may increase the risks of future CO₂-induced ocean acidification on the production of S. japonica. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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27 pages, 1816 KiB

Open AccessArticle

Salt Stress Tolerance in Casuarina glauca: Insights from the Branchlets Transcriptome

by Isabel Fernandes, Octávio S. Paulo, Isabel Marques, Indrani Sarjkar, Arnab Sen, Inês Graça, Katharina Pawlowski, José C. Ramalho and Ana I. Ribeiro-Barros

Plants 2022, 11(21), 2942; https://doi.org/10.3390/plants11212942 - 01 Nov 2022

Cited by 2 | Viewed by 2240

Abstract

Climate change and the accelerated rate of population growth are imposing a progressive degradation of natural ecosystems worldwide. In this context, the use of pioneer trees represents a powerful approach to reverse the situation. Among others, N₂-fixing actinorhizal trees constitute important [...] Read more.

Climate change and the accelerated rate of population growth are imposing a progressive degradation of natural ecosystems worldwide. In this context, the use of pioneer trees represents a powerful approach to reverse the situation. Among others, N₂-fixing actinorhizal trees constitute important elements of plant communities and have been successfully used in land reclamation at a global scale. In this study, we have analyzed the transcriptome of the photosynthetic organs of Casuarina glauca (branchlets) to unravel the molecular mechanisms underlying salt stress tolerance. For that, C. glauca plants supplied either with chemical nitrogen (KNO₃⁺) or nodulated by Frankia (NOD⁺) were exposed to a gradient of salt concentrations (200, 400, and 600 mM NaCl) and RNA-Seq was performed. An average of ca. 25 million clean reads was obtained for each group of plants, corresponding to 86,202 unigenes. The patterns of differentially expressed genes (DEGs) clearly separate two groups: (i) control- and 200 mM NaCl-treated plants, and (ii) 400 and 600 mM NaCl-treated plants. Additionally, although the number of total transcripts was relatively high in both plant groups, the percentage of significant DEGs was very low, ranging from 6 (200 mM NaCl/NOD⁺) to 314 (600 mM NaCl/KNO₃⁺), mostly involving down-regulation. The vast majority of up-regulated genes was related to regulatory processes, reinforcing the hypothesis that some ecotypes of C. glauca have a strong stress-responsive system with an extensive set of constitutive defense mechanisms, complemented by a tight mechanism of transcriptional and post-transcriptional regulation. The results suggest that the robustness of the stress response system in C. glauca is regulated by a limited number of genes that tightly regulate detoxification and protein/enzyme stability, highlighting the complexity of the molecular interactions leading to salinity tolerance in this species. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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22 pages, 14138 KiB

Open AccessArticle

Investigating NAC Transcription Factor Role in Redox Homeostasis in Solanum lycopersicum L.: Bioinformatics, Physiological and Expression Analysis under Drought Stress

by Nagendra Rai, Krishna Kumar Rai, Manish Kumar Singh, Jagdish Singh and Prashant Kaushik

Plants 2022, 11(21), 2930; https://doi.org/10.3390/plants11212930 - 31 Oct 2022

Cited by 1 | Viewed by 1508

Abstract

NAC transcription factors regulate stress-defence pathways and developmental processes in crop plants. However, their detailed functional characterization in tomatoes needs to be investigated comprehensively. In the present study, tomato hybrids subjected to 60 and 80 days of drought stress conditions showed a significant [...] Read more.

NAC transcription factors regulate stress-defence pathways and developmental processes in crop plants. However, their detailed functional characterization in tomatoes needs to be investigated comprehensively. In the present study, tomato hybrids subjected to 60 and 80 days of drought stress conditions showed a significant increase in membrane damage and reduced relative water, chlorophyll and proline content. However, hybrids viz., VRTH-16-3 and VRTH-17-68 showed superior growth under drought stress, as they were marked with low electrolytic leakage, enhanced relative water content, proline content and an enhanced activity of enzymatic antioxidants, along with the upregulation of NAC and other stress-defence pathway genes. Candidate gene(s) exhibiting maximum expression in all the hybrids under drought stress were subjected to detailed in silico characterization to provide significant insight into its structural and functional classification. The homology modelling and superimposition analysis of predicted tomato NAC protein showed that similar amino acid residues were involved in forming the conserved WKAT domain. DNA docking discovered that the SlNAC1 protein becomes activated and exerts a stress-defence response after the possible interaction of conserved DNA elements using Pro⁷², Asn⁷³, Trp⁸¹, Lys⁸², Ala⁸³, Thr⁸⁴, Gly⁸⁵, Thr⁸⁶ and Asp⁸⁷ residues. A protein–protein interaction analysis identified ten functional partners involved in the induction of stress-defence tolerance. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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18 pages, 2276 KiB

Open AccessEditor’s ChoiceArticle

Effect of Plant Growth Regulators on Osmotic Regulatory Substances and Antioxidant Enzyme Activity of Nitraria tangutorum

by Dom Alizet Didi, Shiping Su, Faisal Eudes Sam, Richard John Tiika and Xu Zhang

Plants 2022, 11(19), 2559; https://doi.org/10.3390/plants11192559 - 28 Sep 2022

Cited by 8 | Viewed by 2423

Abstract

Plant growth regulators (PGRs) are natural hormones and synthetic hormone analogues. At low concentrations, PGRs have the ability to influence cell division, cell expansion, and cell structure and function, in addition to mediating environmental stress. In this study, experiments were conducted to determine [...] Read more.

Plant growth regulators (PGRs) are natural hormones and synthetic hormone analogues. At low concentrations, PGRs have the ability to influence cell division, cell expansion, and cell structure and function, in addition to mediating environmental stress. In this study, experiments were conducted to determine how exogenous PGRs indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA) influenced osmotic regulatory substances and activity of antioxidant enzymes in Nitraria tangutorum. Using a completely randomized design, IAA, ABA, and GA3 were applied as foliar spray at concentrations of 50 mg/L, 100 mg/L, 150 mg/L, and 200 mg/L to N. tangutorum shrubs. Some selected shrubs did not receive any treatment and served as the control (Ck). The results showed that the foliar spray of IAA, ABA, and GA3 significantly increased the content of osmotic regulatory substances (soluble sugar, soluble protein, and proline) and antioxidant enzymes (SOD and POD) at most concentrations. In addition, the malondialdehyde (MDA) content significantly reduced after treatment, but after regrowth of coppiced shrubs, lipid peroxidation increased and was still lower than Ck. Our study provides evidence that 100 mg/L 150 mg/L, and 200 mg/L concentrations of IAA, ABA, and GA3 treatments are effective for enhancing osmotic regulatory substances and the activity of antioxidant enzymes in N. tangutorum, which offers an effective strategy not only for increasing tolerance to abiotic and biotic stresses, but also improving the adaptability of N. tangutorum shrubs to the environment. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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19 pages, 3272 KiB

Open AccessEditor’s ChoiceArticle

Magnetic Water Treatment: An Eco-Friendly Irrigation Alternative to Alleviate Salt Stress of Brackish Water in Seed Germination and Early Seedling Growth of Cotton (Gossypium hirsutum L.)

by Jihong Zhang, Quanjiu Wang, Kai Wei, Yi Guo, Weiyi Mu and Yan Sun

Plants 2022, 11(11), 1397; https://doi.org/10.3390/plants11111397 - 25 May 2022

Cited by 8 | Viewed by 3294

Abstract

Magnetized water has been a promising approach to improve crop productivity but the conditions for its effectiveness remain contradictory and inconclusive. The objective of this research was to understand the influences of different magnetized water with varying quality on seed absorption, germination, and [...] Read more.

Magnetized water has been a promising approach to improve crop productivity but the conditions for its effectiveness remain contradictory and inconclusive. The objective of this research was to understand the influences of different magnetized water with varying quality on seed absorption, germination, and early growth of cotton. To this end, a series of experiments involving the seed soaking process, germination test, and pot experiment were carried out to study the effects of different qualities (fresh and brackish water) of magnetized water on seed water absorption, germination, seedling growth, photosynthetic characteristics, and biomass of cotton in 2018. The results showed that the maximum relative water absorption of magnetized fresh and magnetized brackish water relatively increased by 16.76% and 19.75%, respectively, and the magnetic effect time of brackish water was longer than fresh water. The relative promotion effect of magnetized brackish water on cotton seed germination and growth potential was greater than magnetized fresh water. The cotton seeds germination rate under magnetized fresh and magnetized brackish water irrigation relatively increased by 13.14% and 41.86%, respectively, and the relative promoting effect of magnetized brackish water on the vitality indexes and the morphological indexes of cotton seedlings was greater than magnetized fresh water. Unlike non-magnetized water, the net photosynthetic rate (P_n), transpiration rate (T_r), and instantaneous water use efficiency (iWUE) of cotton irrigated with magnetized water increased significantly, while the stomatal limit value (L_s) decreased. The influences of photosynthesis and water use efficiency of cotton under magnetized brackish water were greater than magnetized fresh water. Magnetized fresh water had no significant effect on biomass proportional distribution of cotton but magnetized brackish water irrigation markedly improved the root-to-stem ratio of cotton within a 35.72% range. Therefore, the magnetization of brackish water does improve the growth characteristics of cotton seedlings, and the biological effect of magnetized brackish water is more significant than that of fresh water. It is suggested that magnetized brackish water can be used to irrigate cotton seedlings when freshwater resources are insufficient. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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16 pages, 2616 KiB

Open AccessArticle

High Temperature Alters Anthocyanin Concentration and Composition in Grape Berries of Malbec, Merlot, and Pinot Noir in a Cultivar-Dependent Manner

by Inés de Rosas, Leonor Deis, Yésica Baldo, Juan B. Cavagnaro and Pablo F. Cavagnaro

Plants 2022, 11(7), 926; https://doi.org/10.3390/plants11070926 - 30 Mar 2022

Cited by 15 | Viewed by 2588

Abstract

Climate is determinant for grapevine geographical distribution, berry attributes, and wine quality. Due to climate change, a 2–4 °C increase in mean diurnal temperature is predicted by the end of the century for the most important Argentine viticulture region. We hypothesize that such [...] Read more.

Climate is determinant for grapevine geographical distribution, berry attributes, and wine quality. Due to climate change, a 2–4 °C increase in mean diurnal temperature is predicted by the end of the century for the most important Argentine viticulture region. We hypothesize that such temperature increase will affect color intensity and other quality attributes of red grapes and wines. The present study investigated the effect of high temperature (HT) on anthocyanin concentration and composition, pH, and resveratrol and solids content in berries of three major wine-producing varieties during fruit ripening in two seasons. To this end, a structure that increased mean diurnal temperature by 1.5–2.0 °C at berry sites, compared to Control (C) plants grown without such structure, was implemented in field grown vineyards of Malbec, Merlot, and Pinot Noir. Results revealed a cultivar-dependent response to HT conditions, with Malbec and Pinot Noir berries exhibiting significant decreases in total anthocyanin concentration (TAC) at veraison and harvest, respectively, while Merlot maintained an unaffected pigment content under HT. The decrease in TAC was associated with reduced levels of delphinidin, cyanidin, petunidin, peonidin, and malvidin glycosides, and increased ratios of acylated (AA)/non-acylated anthocyanins (NAA), suggesting pigment acylation as a possible stress-response mechanism for attenuating HT negative effects. Under HT, Pinot Noir, which does not produce AA, was the only cultivar with lower TAC at harvest (p < 0.05). pH, resveratrol, and solids content were not affected by HT. Our results predict high, medium, and low plasticity with regard to color quality attributes for Malbec, Merlot, and Pinot Noir, respectively, in the context of climate change. Full article

(This article belongs to the Special Issue Physiological and Biochemical Adjustments in Response to Abiotic Stressors Associated with Climate Change)

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