Research

27 pages, 14927 KiB

Open AccessArticle

‘Honeycrisp’ Bitter Pit Response to Rootstock and Region under Eastern New York Climatic Conditions

by Daniel J. Donahue, Gemma Reig Córdoba, Sarah E. Elone, Anna E. Wallis and Michael R. Basedow

Plants 2021, 10(5), 983; https://doi.org/10.3390/plants10050983 - 14 May 2021

Cited by 9 | Viewed by 1947

There are still unknown factors at play in the causation of bitter pit in ‘Honeycrisp’ as well as in other apple varieties. To investigate some of these factors, we conducted a survey of 34 ‘Honeycrisp’ orchard blocks distributed across two disparate production regions [...] Read more.

There are still unknown factors at play in the causation of bitter pit in ‘Honeycrisp’ as well as in other apple varieties. To investigate some of these factors, we conducted a survey of 34 ‘Honeycrisp’ orchard blocks distributed across two disparate production regions in eastern New York State, representing a variety of rootstocks, over three growing seasons. Weather, soil, horticultural traits, fruit quality traits, pick timing, leaf and peel minerals were evaluated for their impact on bitter pit (BP) incidence; factors were further evaluated for their interaction with region and rootstock. ‘Honeycrisp’ trees on B.9 rootstock were smaller but with comparable terminal shoot growth when compared to those on M.26 and M.9 rootstocks. B.9 fruits, which had similar fruit size to M.26 and M.9 and had good fruit quality at harvest and after storage, were much less likely to express bitter pit symptoms compared to M.9 and M.26 rootstocks. Not all traits evaluated individually correlated significatively with bitter pit incidence after a period in storage. Depending on rootstock and region, the correlation could be significant in one situation, with no correlation at all in another. In this study, peel Mg/Ca ratio and peel Ca correlated with BP for all three rootstocks, with the strongest correlations associated with the M.9 clones. These same traits correlated with BP for both regions. Pick timing had a significant influence on BP incidence following storage, with later picks offering better bitter pit storage performance. While excessively large fruits, those in the 48 and 56 count size categories, were found to be highly susceptible to BP regardless of rootstock, B.9 BP fruit susceptibility for smaller sizes was found to be size neutral. A PLSR prediction model for each rootstock and each region showed that different variables correlated to BP depending on the situation. Thus, the results could suggest that in addition to the variables considered in this study, there are other less studied factors that can influence the expression of BP symptoms. We strongly suggest that rootstock BP performance be considered a critical parameter when planning a commercial ‘Honeycrisp’ orchard and be evaluated in rootstock breeding and development programs prior to wide commercial release. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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15 pages, 1673 KiB

Open AccessArticle

Soil and Regulated Deficit Irrigation Affect Growth, Yield and Quality of ‘Nero d’Avola’ Grapes in a Semi-Arid Environment

by Maria Gabriella Barbagallo, Giuseppe Vesco, Rosario Di Lorenzo, Riccardo Lo Bianco and Antonino Pisciotta

Plants 2021, 10(4), 641; https://doi.org/10.3390/plants10040641 - 28 Mar 2021

Cited by 14 | Viewed by 2352

Abstract

The present work studied the effect of two consecutive years of regulated deficit irrigation (RDI) compared to rain fed management on the vegetative growth, yield, and quality of ‘Nero d’Avola’ grapes. The trial was conducted separately in two soils (vertisol and entisol) located [...] Read more.

The present work studied the effect of two consecutive years of regulated deficit irrigation (RDI) compared to rain fed management on the vegetative growth, yield, and quality of ‘Nero d’Avola’ grapes. The trial was conducted separately in two soils (vertisol and entisol) located at the top and bottom hillside of the same vineyard. Vertisol was characterized by greater depth, organic matter, exchangeable K₂O, and total N than entisol. RDI was based on an irrigation volume at 25% of estimated crop evapotranspiration (ET_c) up to end of veraison and 10% of estimated ET_c up to 15 days before harvest. Predawn water potential (PDWP) was used as indicator of plant water status and irrigation timing. No difference in irrigation management was evident between vertisol and entisol. Under Mediterranean climate conditions, RDI was able to enhance grape yield and vegetative growth, especially in vertisol, but it reduced berry titratable acidity and total anthocyanins. ‘Nero d’Avola’ showed to adapt to drought conditions in the open field. Both soil type and irrigation regimes may provide opportunities to obtain different ‘Nero d’Avola’ wine quality and boost typicality. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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16 pages, 694 KiB

Open AccessArticle

Modelling Soluble Solids Content Accumulation in ‘Braeburn’ Apples

by Konni Biegert, Daniel Stöckeler, Roy J. McCormick and Peter Braun

Plants 2021, 10(2), 302; https://doi.org/10.3390/plants10020302 - 05 Feb 2021

Cited by 8 | Viewed by 2547

Abstract

Optical sensor data can be used to determine changes in anthocyanins, chlorophyll and soluble solids content (SSC) in apple production. In this study, visible and near-infrared spectra (729 to 975 nm) were transformed to SSC values by advanced multivariate calibration models i.e., partial [...] Read more.

Optical sensor data can be used to determine changes in anthocyanins, chlorophyll and soluble solids content (SSC) in apple production. In this study, visible and near-infrared spectra (729 to 975 nm) were transformed to SSC values by advanced multivariate calibration models i.e., partial least square regression (PLSR) in order to test the substitution of destructive chemical analyses through non-destructive optical measurements. Spectral field scans were carried out from 2016 to 2018 on marked ‘Braeburn’ apples in Southwest Germany. The study combines an in-depth statistical analyses of longitudinal SSC values with horticultural knowledge to set guidelines for further applied use of SSC predictions in the orchard to gain insights into apple carbohydrate physiology. The PLSR models were investigated with respect to sample size, seasonal variation, laboratory errors and the explanatory power of PLSR models when applied to independent samples. As a result of Monte Carlo simulations, PLSR modelled SSC only depended to a minor extent on the absolute number and accuracy of the wet chemistry laboratory calibration measurements. The comparison between non-destructive SSC determinations in the orchard with standard destructive lab testing at harvest on an independent sample showed mean differences of 0.5% SSC over all study years. SSC modelling with longitudinal linear mixed-effect models linked high crop loads to lower SSC values at harvest and higher SSC values for fruit from the top part of a tree. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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16 pages, 3634 KiB

Open AccessFeature PaperArticle

Detecting Mild Water Stress in Olive with Multiple Plant-Based Continuous Sensors

by Giulia Marino, Alessio Scalisi, Paula Guzmán-Delgado, Tiziano Caruso, Francesco Paolo Marra and Riccardo Lo Bianco

Plants 2021, 10(1), 131; https://doi.org/10.3390/plants10010131 - 11 Jan 2021

Cited by 19 | Viewed by 3227

Abstract

A comprehensive characterization of water stress is needed for the development of automated irrigation protocols aiming to increase olive orchard environmental and economical sustainability. The main aim of this study is to determine whether a combination of continuous leaf turgor, fruit growth, and [...] Read more.

A comprehensive characterization of water stress is needed for the development of automated irrigation protocols aiming to increase olive orchard environmental and economical sustainability. The main aim of this study is to determine whether a combination of continuous leaf turgor, fruit growth, and sap flow responses improves the detection of mild water stress in two olive cultivars characterized by different responses to water stress. The sensitivity of the tested indicators to mild stress depended on the main mechanisms that each cultivar uses to cope with water deficit. One cultivar showed pronounced day to day changes in leaf turgor and fruit relative growth rate in response to water withholding. The other cultivar reduced daily sap flows and showed a pronounced tendency to reach very low values of leaf turgor. Based on these responses, the sensitivity of the selected indicators is discussed in relation to drought response mechanisms, such as stomatal closure, osmotic adjustment, and tissue elasticity. The analysis of the daily dynamics of the monitored parameters highlights the limitation of using non-continuous measurements in drought stress studies, suggesting that the time of the day when data is collected has a great influence on the results and consequent interpretations, particularly when different genotypes are compared. Overall, the results highlight the need to tailor plant-based water management protocols on genotype-specific physiological responses to water deficit and encourage the use of combinations of plant-based continuously monitoring sensors to establish a solid base for irrigation management. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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16 pages, 4492 KiB

Open AccessArticle

Red and Blue Netting Alters Leaf Morphological and Physiological Characteristics in Apple Trees

by Richard M. Bastías, Pasquale Losciale, Camilla Chieco and Luca Corelli-Grappadelli

Plants 2021, 10(1), 127; https://doi.org/10.3390/plants10010127 - 09 Jan 2021

Cited by 11 | Viewed by 2792

Abstract

There is little information about the role of red and blue light on leaf morphology and physiology in fruit trees, and more studies have been developed in herbaceous plants grown under controlled light conditions. The objective of this research was to evaluate the [...] Read more.

There is little information about the role of red and blue light on leaf morphology and physiology in fruit trees, and more studies have been developed in herbaceous plants grown under controlled light conditions. The objective of this research was to evaluate the effect of red and blue screens on morpho-anatomy and gas exchange in apple leaves grown under ambient sunlight conditions. Apple trees cv. Fuji were covered by 40% red and blue nets, leaving trees with 20% white net as control. Light relations (photosynthetic photon flux density, PPFD; red to far-red light ratio, R/FR and blue to red light ratio, B/R), morpho-anatomical features of the leaf (palisade to spongy mesophyll ratio, P/S, and stomata density, SD) and leaf gas exchange (net photosynthesis rate, A_n; stomatal conductance, g_s; transpiration rate, E; and intrinsic water use efficiency, IWUE) were evaluated. Red and blue nets reduced 27% PPFD, reducing by 20% SD and 25% P/S compared to control, but without negative effects on A_n and g_s. Blue net increased g_s 21%, leading to the highest E and lowest IWUE by increment of B/R light proportion. These findings demonstrate the potential use of red and blue nets for differential modulation of apple leaf gas exchange through sunlight management under field conditions. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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23 pages, 7091 KiB

Open AccessArticle

Russeting in Apple is Initiated after Exposure to Moisture Ends: Molecular and Biochemical Evidence

by Jannis Straube, Yun-Hao Chen, Bishnu P. Khanal, Alain Shumbusho, Viktoria Zeisler-Diehl, Kiran Suresh, Lukas Schreiber, Moritz Knoche and Thomas Debener

Plants 2021, 10(1), 65; https://doi.org/10.3390/plants10010065 - 30 Dec 2020

Cited by 19 | Viewed by 3692

Abstract

Exposure of the fruit surface to moisture during early development is causal in russeting of apple (Malus × domestica Borkh.). Moisture exposure results in formation of microcracks and decreased cuticle thickness. Periderm differentiation begins in the hypodermis, but only after discontinuation of [...] Read more.

Exposure of the fruit surface to moisture during early development is causal in russeting of apple (Malus × domestica Borkh.). Moisture exposure results in formation of microcracks and decreased cuticle thickness. Periderm differentiation begins in the hypodermis, but only after discontinuation of moisture exposure. Expressions of selected genes involved in cutin, wax and suberin synthesis were quantified, as were the wax, cutin and suberin compositions. Experiments were conducted in two phases. In Phase I (31 days after full bloom) the fruit surface was exposed to moisture for 6 or 12 d. Phase II was after moisture exposure had been discontinued. Unexposed areas on the same fruit served as unexposed controls. During Phase I, cutin and wax synthesis genes were down-regulated only in the moisture-exposed patches. During Phase II, suberin synthesis genes were up-regulated only in the moisture-exposed patches. The expressions of cutin and wax genes in the moisture-exposed patches increased slightly during Phase II, but the levels of expression were much lower than in the control patches. Amounts and compositions of cutin, wax and suberin were consistent with the gene expressions. Thus, moisture-induced russet is a two-step process: moisture exposure reduces cutin and wax synthesis, moisture removal triggers suberin synthesis. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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15 pages, 1581 KiB

Open AccessArticle

Gibberellic Acid Modifies the Transcript Abundance of ABA Pathway Orthologs and Modulates Sweet Cherry (Prunus avium) Fruit Ripening in Early- and Mid-Season Varieties

by Nathalie Kuhn, Claudio Ponce, Macarena Arellano, Alson Time, Boris Sagredo, José Manuel Donoso and Lee A. Meisel

Plants 2020, 9(12), 1796; https://doi.org/10.3390/plants9121796 - 18 Dec 2020

Cited by 16 | Viewed by 3020

Abstract

Several phytohormones modulate ripening in non-climacteric fruits, which is triggered by abscisic acid (ABA). Gibberellins (GAs) are present during the onset of ripening in sweet cherry fruits, and exogenous gibberellic acid (GA₃) application delays ripening, though this effect is variety-dependent. Although [...] Read more.

Several phytohormones modulate ripening in non-climacteric fruits, which is triggered by abscisic acid (ABA). Gibberellins (GAs) are present during the onset of ripening in sweet cherry fruits, and exogenous gibberellic acid (GA₃) application delays ripening, though this effect is variety-dependent. Although an ABA accumulation delay has been reported following GA₃ treatment, the mechanism by which GA modulates this process has not been investigated at the molecular level in sweet cherry. Therefore, the aim of this work is to analyze the effect of GA₃ on the fruit ripening process and the transcript levels of ABA pathway orthologs in two varieties having different maturity time phenotypes. The early-season variety had a rapid transition from yellow to pink fruit color, whereas pink color initiation took longer in the mid-season variety. GA₃ increased the proportion of lighter colored fruits at ripeness in both varieties, but it produced a delay in IAD—a ripening index—only in the mid-season variety. This delay was accompanied by an increased transcript abundance of PavPP2Cs, which are putative negative regulators of the ABA pathway. On the other hand, the early-season variety had increased expression of PavCYP707A2—a putative ABA catabolic gene–, and reduced transcript levels of PavPP2Cs and SnRK2s after the GA₃ treatment. Together these results show that GA modulates fruit ripening, exerting its action in part by interacting with the ABA pathway in sweet cherry. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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21 pages, 2109 KiB

Open AccessEditor’s ChoiceArticle

Correction of Potassium Fertigation Rate of Apple Tree (Malus domestica Borkh.) in Central Russia during the Growing Season

by Andrei I. Kuzin, Natalia Ya. Kashirskaya, Anna M. Kochkina and Alexey V. Kushner

Plants 2020, 9(10), 1366; https://doi.org/10.3390/plants9101366 - 15 Oct 2020

Cited by 23 | Viewed by 2907

Abstract

The proper use of potassium fertilizer can stimulate a significant yield increase. However, the application of excessively high rates of potassium can reduce the availability of soil calcium for apple trees. The potassium fertigation rate must meet the apple tree’s requirements so that [...] Read more.

The proper use of potassium fertilizer can stimulate a significant yield increase. However, the application of excessively high rates of potassium can reduce the availability of soil calcium for apple trees. The potassium fertigation rate must meet the apple tree’s requirements so that the applied fertilizers can be absorbed by the roots as much as possible. Crop load in apple orchards sometimes varies significantly in different years. The potassium content in apple fruits is relatively high, and the maximum requirement for this nutrient occurs when fruits grow and ripen. Different crop loads at that time mean the various demands of trees and need for changing application rates for this nutrient. The investigation was carried out in the experimental orchard of I.V. Michurin Federal Scientific Centre (Michurinsk, Russia) in 2016 and 2017 (52.885131, 40.465613). We studied seasonal changes of potassium and calcium contents in soil, fruits, and leaves and their relationship with yield during the research. We paid much attention to the potassium rate shift on its content in leaves and fruits and cultivars “Lobo” and “Zhigulevskoye” yield. If the potassium application rate changes according to the actual crop load, it stimulates the yield growth or (if the crop load was relatively low) the reduction of the rate did not lower the productivity. Moreover, we studied the relationship between potassium and calcium nutrition. The decrease in potassium fertigation rate increased the availability of soil calcium. It was the reason for fruit calcium concentration enlargement and mitigation of the K/Ca ratio. We also specified some parameters for soil–leaf diagnosis for potassium nutrition during the growing season. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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10 pages, 1670 KiB

Open AccessArticle

The Influence of Environmental Features on the Morphometric Variation in Mauritia flexuosa L.f. Fruits and Seeds

by Nilo L. Sander, Carolina J. da Silva, Aline V. M. Duarte, Bruno W. Zago, Carla Galbiati, Iris G. Viana, Joari C. de Arruda, Juliana E. Dardengo, Juliana P. Poletine, Marcelo H. Siqueira Leite, Marta H. S. de Souza, Robson F. de Oliveira, Thallita S. Guimarães, Valvenarg P. da Silva and Marco A. A. Barelli

Plants 2020, 9(10), 1304; https://doi.org/10.3390/plants9101304 - 02 Oct 2020

Cited by 4 | Viewed by 2075

Abstract

The environmental heterogeneity may reflect the different morphological and phenotypic traits of individuals belonging to a single species. We used 14 morphological traits of Mauritia flexuosa L.f. to understanding the relation between environment and phenotypic traits. Twenty-five fruits were collected from each of [...] Read more.

The environmental heterogeneity may reflect the different morphological and phenotypic traits of individuals belonging to a single species. We used 14 morphological traits of Mauritia flexuosa L.f. to understanding the relation between environment and phenotypic traits. Twenty-five fruits were collected from each of the 10 individuals sampled in each study site: Chapada dos Guimarães (CG), Vila Bela da Santíssima Trindade (VB), and Alta Floresta (AF). We analyzed the genetic divergence, using the standardized Euclidean distance, the sequential method of Tocher, unweighted pair group method with arithmetic mean (UPGMA), and the projection of the distances onto 2D plane, and calculated the relative importance of the traits evaluated. The analysis showed the partition of individuals into three main groups: Two groups comprising the majority of individuals. Fresh fruit weight, pulp rate, fresh pulp weight, and moisture rate were the traits that most helped explaining the difference between materials. The results shown in the current study evidenced the influence of these three different environments on the biometric traits of M. flexuosa. Such influence has led to the formation of Alta Floresta and Vila Bela da Santíssima Trindade individuals in different groups, whereas the Chapada dos Guimarães individuals were able to permeate the two other groups, although they showed stronger tendency to group with individuals from Vila Bela da Santíssima Trindade. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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18 pages, 8504 KiB

Open AccessArticle

Russeting in Apple Is Initiated After Exposure to Moisture Ends—I. Histological Evidence

by Yun-Hao Chen, Jannis Straube, Bishnu P. Khanal, Moritz Knoche and Thomas Debener

Plants 2020, 9(10), 1293; https://doi.org/10.3390/plants9101293 - 30 Sep 2020

Cited by 23 | Viewed by 2953

Abstract

Russeting (periderm formation) is a critical fruit-surface disorder in apple (Malus × domestica Borkh.). The first symptom of insipient russeting is cuticular microcracking. Humid and rainy weather increases russeting. The aim was to determine the ontogeny of moisture-induced russeting in ‘Pinova’ apple. [...] Read more.

Russeting (periderm formation) is a critical fruit-surface disorder in apple (Malus × domestica Borkh.). The first symptom of insipient russeting is cuticular microcracking. Humid and rainy weather increases russeting. The aim was to determine the ontogeny of moisture-induced russeting in ‘Pinova’ apple. We recorded the effects of duration of exposure to water and the stage of fruit development at exposure on microcracking, periderm formation and cuticle deposition. Early on (21 or 31 days after full bloom; DAFB) short periods (2 to 12 d) of moisture exposure induced cuticular microcracking—but not later on (66 or 93 DAFB). A periderm was not formed during moisture exposure but 4 d after exposure ended. A periderm was formed in the hypodermis beneath a microcrack. Russeting frequency and severity were low for up to 4 d of moisture exposure but increased after 6 d. Cuticle thickness was not affected by moisture for up to 8 d but decreased for longer exposures. Cuticular ridge thickness decreased around a microcrack. In general, moisture did not affect cuticular strain release. We conclude that a hypodermal periderm forms after termination of moisture exposure and after microcrack formation. Reduced cuticle deposition may cause moisture-induced microcracking and, thus, russeting. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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20 pages, 2665 KiB

Open AccessArticle

Gaining Insight into Exclusive and Common Transcriptomic Features Linked to Drought and Salinity Responses across Fruit Tree Crops

by Jubina Benny, Annalisa Marchese, Antonio Giovino, Francesco Paolo Marra, Anna Perrone, Tiziano Caruso and Federico Martinelli

Plants 2020, 9(9), 1059; https://doi.org/10.3390/plants9091059 - 19 Aug 2020

Cited by 10 | Viewed by 2943

Abstract

The present study aimed at identifying and mapping key genes expressed in root tissues involved in drought and salinity tolerance/resistance conserved among different fruit tree species. Twenty-six RNA-Seq samples were analyzed from six published studies in five plant species (Olea europaea, Vitis [...] Read more.

The present study aimed at identifying and mapping key genes expressed in root tissues involved in drought and salinity tolerance/resistance conserved among different fruit tree species. Twenty-six RNA-Seq samples were analyzed from six published studies in five plant species (Olea europaea, Vitis riparia Michx, Prunus mahaleb, Prunus persica, Phoenix dactylifera). This meta-analysis used a bioinformatic pipeline identifying 750 genes that were commonly modulated in three salinity studies and 683 genes that were commonly regulated among three drought studies, implying their conserved role in resistance/tolerance/response to these environmental stresses. A comparison was done on the genes that were in common among both salinity and drought resulted in 82 genes, of which 39 were commonly regulated with the same trend of expression (23 were upregulated and 16 were downregulated). Gene set enrichment and pathway analysis pointed out that pathways encoding regulation of defense response, drug transmembrane transport, and metal ion binding are general key molecular responses to these two abiotic stress responses. Furthermore, hormonal molecular crosstalk plays an essential role in the fine-tuning of plant responses to drought and salinity. Drought and salinity induced a different molecular “hormonal fingerprint”. Dehydration stress specifically enhanced multiple genes responsive to abscisic acid, gibberellin, brassinosteroids, and the ethylene-activated signaling pathway. Salt stress mostly repressed genes encoding for key enzymes in signaling proteins in auxin-, gibberellin-(gibberellin 2 oxidase 8), and abscisic acid-related pathways (aldehyde oxidase 4, abscisic acid-responsive element-binding protein 3). Abiotic stress-related genes were mapped into the chromosome to identify molecular markers usable for the improvement of these complex quantitative traits. This meta-analysis identified genes that serve as potential targets to develop cultivars with enhanced drought and salinity resistance and/or tolerance across different fruit tree crops in a biotechnological sustainable way. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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18 pages, 3303 KiB

Open AccessArticle

Russeting in ‘Apple’ Mango: Triggers and Mechanisms

by Thomas O. Athoo, Andreas Winkler and Moritz Knoche

Plants 2020, 9(7), 898; https://doi.org/10.3390/plants9070898 - 16 Jul 2020

Cited by 13 | Viewed by 9547

Abstract

Russeting is an important surface disorder of many fruitcrop species. The mango cultivar ‘Apple’ is especially susceptible to russeting. Russeting compromises both fruit appearance and postharvest performance. The objective was to identify factors, mechanisms, and consequences of russeting in ‘Apple’ mango. Russeting was [...] Read more.

Russeting is an important surface disorder of many fruitcrop species. The mango cultivar ‘Apple’ is especially susceptible to russeting. Russeting compromises both fruit appearance and postharvest performance. The objective was to identify factors, mechanisms, and consequences of russeting in ‘Apple’ mango. Russeting was quantified on excised peels using image analysis and a categorical rating scheme. Water vapour loss was determined gravimetrically. The percentage of the skin area exhibiting russet increased during development. Russet began at lenticels then spread across the surface, ultimately forming a network of rough, brown patches over the skin. Cross-sections revealed stacks of phellem cells, typical of a periderm. Russet was more severe on the dorsal surface of the fruit than on the ventral and more for fruit in the upper part of the canopy than in the lower. Russet differed markedly across orchards sites of different climates. Russet was positively correlated with altitude, the number of rainy days, and the number of cold nights but negatively correlated with minimum, maximum, and mean daily temperatures, dew point temperature, and heat sum. Russeted fruit had higher transpiration rates than non-russeted fruits and higher skin permeance to water vapour. Russet in ‘Apple’ mango is due to periderm formation that is initiated at lenticels. Growing conditions conducive for surface wetness exacerbate russeting. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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14 pages, 910 KiB

Open AccessArticle

Biochemical Analysis of Organic Acids and Soluble Sugars in Wild and Cultivated Pomegranate Germplasm Based in Pakistan

by Muhammad Nafees, Muhammad Jafar Jaskani, Ishtiaq Ahmad, Maryam, Irfan Ashraf, Ambreen Maqsood, Sunny Ahmar, Muhammad Azam, Sajjad Hussain, Asma Hanif and Jen-Tsung Chen

Plants 2020, 9(4), 493; https://doi.org/10.3390/plants9040493 - 11 Apr 2020

Cited by 12 | Viewed by 3667

Abstract

Pomegranate is famous for its health benefiting chemical and biochemical constituent compounds. The present study was undertaken to characterize pomegranate germplasm for its various fruit traits, acids, and sugar profiling through high performance liquid chromatography (HPLC) analysis. Among 11 detected acids and 8 [...] Read more.

Pomegranate is famous for its health benefiting chemical and biochemical constituent compounds. The present study was undertaken to characterize pomegranate germplasm for its various fruit traits, acids, and sugar profiling through high performance liquid chromatography (HPLC) analysis. Among 11 detected acids and 8 sugars, citric acid and fructose were predominant in 18 domestic and 5 wild genotypes, respectively. Fruit weight, aril weight and wood portion index (WPI) were ranged from 15.82% to 24.42%, 10.99% to 113.78%, and 2.39% to 17.25%, respectively. Genotypes were grouped as sweet, sweet–sour, sour–sweet, and sour based on citric acid contents. Lactic acid and pyruvic acid showed the highest correlation (r = 0.92), however, sour and sweet genotypes had strong association for acids and sugars, respectively. Straddling of dendrogram showed the flow of genetic material in a cultivated location with wild and cultivated pomegranates grouped in different classes, however, wild and sour landraces grouped in the same class with 71% similarity of traits. Based on the observations of the current study, it was concluded that selected wild and arid zones (Multan, Bahawalpur) genotypes are poor in nutrients (acid and sugars) quality, however, genotypes of Rahim-Yar-Khan, Muzafar Garh, and Khyber Pakhtunkhwa have a better composition of sugars and acids. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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15 pages, 3057 KiB

Open AccessArticle

Water Deficit Affects the Growth and Leaf Metabolite Composition of Young Loquat Plants

by Giovanni Gugliuzza, Giuseppe Talluto, Federico Martinelli, Vittorio Farina and Riccardo Lo Bianco

Plants 2020, 9(2), 274; https://doi.org/10.3390/plants9020274 - 19 Feb 2020

Cited by 14 | Viewed by 3584

Abstract

Water scarcity in the Mediterranean area is very common and understanding responses to drought is important for loquat management and production. The objective of this study was to evaluate the effect of drought on the growth and metabolism of loquat. Ninety two-year-old plants [...] Read more.

Water scarcity in the Mediterranean area is very common and understanding responses to drought is important for loquat management and production. The objective of this study was to evaluate the effect of drought on the growth and metabolism of loquat. Ninety two-year-old plants of ‘Marchetto’ loquat grafted on quince were grown in the greenhouse in 12-liter pots and three irrigation regimes were imposed starting on 11 May and lasting until 27 July, 2013. One-third of the plants was irrigated with 100% of the water consumed (well watered, WW), a second group of plants was irrigated with 66% of the water supplied to the WW plants (mild drought, MD), and a third group was irrigated with 33% of the water supplied to the WW plants (severe drought, SD). Minimum water potential levels of −2.0 MPa were recorded in SD plants at the end of May. Photosynthetic rates were reduced according to water supply (WW > MD > SD), especially during the morning hours. By the end of the trial, severe drought reduced all growth parameters and particularly leaf growth. Drought induced early accumulation of sorbitol in leaves, whereas other carbohydrates were not affected. Of over 100 leaf metabolites investigated, 9 (squalene, pelargonic acid, glucose-1-phosphate, palatinol, capric acid, aconitic acid, xylitol, lauric acid, and alanine) were found to be useful to discriminate between the three irrigation groups, suggesting their involvement in loquat metabolism under drought conditions. Loquat behaved as a moderately drought-tolerant species (limited stem water potential and growth reductions) and the accumulation of sorbitol in favor of sucrose in mildly-stressed plants may be considered an early protective mechanism against leaf dehydration and a potential biochemical marker for precise irrigation management. Full article

(This article belongs to the Special Issue Physiological Responses of Tree Fruits to Environmental and Management Factors)

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