Plants

1668 KiB

Open AccessArticle

Interaction Effect between Elevated CO₂ and Fertilization on Biomass, Gas Exchange and C/N Ratio of European Beech (Fagus sylvatica L.)

by Neda Lotfiomran, Michael Köhl and Jörg Fromm

Plants 2016, 5(3), 38; https://doi.org/10.3390/plants5030038 - 07 Sep 2016

Cited by 23 | Viewed by 6026

Abstract

The effects of elevated CO₂ and interaction effects between elevated CO₂ and nutrient supplies on growth and the C/N ratio of European beech (Fagus sylvatica L.) saplings were studied. One-year-old beech saplings were grown in a greenhouse at ambient (385 [...] Read more.

The effects of elevated CO₂ and interaction effects between elevated CO₂ and nutrient supplies on growth and the C/N ratio of European beech (Fagus sylvatica L.) saplings were studied. One-year-old beech saplings were grown in a greenhouse at ambient (385 ppm) and elevated CO₂ (770 ppm/950 ppm), with or without fertilization for two growing seasons. In this study, emphasis is placed on the combined fertilization including phosphorus, potassium and nitrogen with two level of elevated CO₂. The fertilized plants grown under elevated CO₂ had the highest net leaf photosynthesis rate (Ac). The saplings grown under elevated CO₂ had a significantly lower stomatal conductance (gs) than saplings grown under ambient air. No interaction effect was found between elevated CO₂ and fertilization on Ac. A interaction effect between CO₂ and fertilization, as well as between date and fertilization and between date and CO₂ was detected on gs. Leaf chlorophyll content index (CCI) and leaf nitrogen content were strongly positively correlated to each other and both of them decreased under elevated CO₂. At the end of both growing seasons, stem dry weight was greater under elevated CO₂ and root dry weight was not affected by different treatments. No interaction effect was detected between elevated CO₂ and nutrient supplies on the dry weight of different plant tissues (stems and roots). However, elevated CO₂ caused a significant decrease in the nitrogen content of plant tissues. Nitrogen reduction in the leaves under elevated CO₂ was about 10% and distinctly higher than in the stem and root. The interaction effect of elevated CO₂ and fertilization on C/N ratio in plants tissues was significant. The results led to the conclusion that photosynthesis and the C/N ratio increased while stomatal conductance and leaf nitrogen content decreased under elevated CO₂ and nutrient-limited conditions. In general, under nutrient-limited conditions, the plant responses to elevated CO₂ were decreased. Full article

(This article belongs to the Special Issue Abiotic Environmental Stress Responses of Plants)

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5991 KiB

Open AccessArticle

Structural Properties of Cruciferin and Napin of Brassica napus (Canola) Show Distinct Responses to Changes in pH and Temperature

by Suneru P. Perera, Tara C. McIntosh and Janitha P. D. Wanasundara

Plants 2016, 5(3), 36; https://doi.org/10.3390/plants5030036 - 07 Sep 2016

Cited by 75 | Viewed by 9080

Abstract

The two major storage proteins identified in Brassica napus (canola) were isolated and studied for their molecular composition, structural characteristics and the responses of structural features to the changes in pH and temperature. Cruciferin, a complex of six monomers, has a predominantly β-sheet-containing [...] Read more.

The two major storage proteins identified in Brassica napus (canola) were isolated and studied for their molecular composition, structural characteristics and the responses of structural features to the changes in pH and temperature. Cruciferin, a complex of six monomers, has a predominantly β-sheet-containing secondary structure. This protein showed low pH unstable tertiary structure, and distinctly different solubility behaviour with pH when intact in the seed cellular matrix. Cruciferin structure unfolds at pH 3 even at ambient temperature. Temperature-induced structure unfolding was observed above the maximum denaturation temperature of cruciferin. Napin was soluble in a wider pH range than cruciferin and has α-helices dominating secondary structure. Structural features of napin showed less sensitivity to the changes in medium pH and temperature. The surface hydrophobicity (S₀) and intrinsic fluorescence of tryptophan residue appear to be good indicators of cruciferin unfolding, however they were not the best to demonstrate structural changes of napin. These two storage proteins of B. napus have distinct molecular characteristics, therefore properties and functionalities they provide are contrasting rather than complementary. Full article

(This article belongs to the Special Issue Selected/Extended Full Papers of 14th International Rapeseed Congress)

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1888 KiB

Open AccessArticle

Knockdown of WHIRLY1 Affects Drought Stress-Induced Leaf Senescence and Histone Modifications of the Senescence-Associated Gene HvS40

by Bianka Janack, Paula Sosoi, Karin Krupinska and Klaus Humbeck

Plants 2016, 5(3), 37; https://doi.org/10.3390/plants5030037 - 06 Sep 2016

Cited by 34 | Viewed by 7363

Abstract

The plastid-nucleus located protein WHIRLY1 has been described as an upstream regulator of leaf senescence, binding to the promoter of senescence-associated genes like HvS40. To investigate the impact of WHIRLY1 on drought stress-induced, premature senescence, transgenic barley plants with an RNAi-mediated knockdown [...] Read more.

The plastid-nucleus located protein WHIRLY1 has been described as an upstream regulator of leaf senescence, binding to the promoter of senescence-associated genes like HvS40. To investigate the impact of WHIRLY1 on drought stress-induced, premature senescence, transgenic barley plants with an RNAi-mediated knockdown of the HvWHIRLY1 gene were grown under normal and drought stress conditions. The course of leaf senescence in these lines was monitored by physiological parameters and studies on the expression of senescence- and drought stress-related genes. Drought treatment accelerated leaf senescence in WT plants, whereas WHIRLY 1 knockdown lines (RNAi-W1) showed a stay-green phenotype. Expression of both senescence-associated and drought stress-responsive genes, was delayed in the transgenic plants. Notably, expression of transcription factors of the WRKY and NAC families, which are known to function in senescence- and stress-related signaling pathways, was affected in plants with impaired accumulation of WHIRLY1, indicating that WHIRLY1 acts as an upstream regulator of drought stress-induced senescence. To reveal the epigenetic indexing of HvS40 at the onset of drought-induced senescence in WT and RNAi-W1 lines, stress-responsive loading with histone modifications of promoter and coding sequences of HvS40 was analyzed by chromatin immunoprecipitation and quantified by qRT-PCR. In the wildtype, the euchromatic mark H3K9ac of the HvS40 gene was low under control conditions and was established in response to drought treatment, indicating the action of epigenetic mechanisms in response to drought stress. However, drought stress caused no significant increase in H3K9ac in plants impaired in accumulation of WHIRLY1. The results show that WHIRLY1 knockdown sets in motion a delay in senescence that involves all aspects of gene expression, including changes in chromatin structure. Full article

(This article belongs to the Special Issue Plant Senescence)

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156 KiB

Open AccessCorrection

Correction: Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1. Plants 2015, 4, 691–709

by Anja Smykowski, Stefan M. Fischer and Ulrike Zentgraf

Plants 2016, 5(3), 35; https://doi.org/10.3390/plants5030035 - 01 Sep 2016

Viewed by 3272

Abstract

The authors wish to make the following corrections to their paper [1].[...] Full article

761 KiB

Open AccessArticle

Phenylphenalenones Accumulate in Plant Tissues of Two Banana Cultivars in Response to Herbivory by the Banana Weevil and Banana Stem Weevil

by Dirk Hölscher, Andreas Buerkert and Bernd Schneider

Plants 2016, 5(3), 34; https://doi.org/10.3390/plants5030034 - 25 Aug 2016

Cited by 11 | Viewed by 6363

Abstract

Phenylphenalenone-type compounds accumulated in the tissues of two banana cultivars—Musa acuminata cv. “Grande Naine” (AAA) and Musa acuminata × balbisiana Colla cv. “Bluggoe” (ABB)—when these were fed on by the banana weevil (Cosmopolites sordidus (Germ.) (Coleoptera: Curculionidae)) and the banana stem [...] Read more.

Phenylphenalenone-type compounds accumulated in the tissues of two banana cultivars—Musa acuminata cv. “Grande Naine” (AAA) and Musa acuminata × balbisiana Colla cv. “Bluggoe” (ABB)—when these were fed on by the banana weevil (Cosmopolites sordidus (Germ.) (Coleoptera: Curculionidae)) and the banana stem weevil (Odoiporus longicollis (Oliver) (Coleoptera: Curculionidae)). The chemical constituents of the banana material were separated by means of chromatographic techniques and identified by NMR spectroscopy. One new compound, 2-methoxy-4-phenylphenalen-1-one, was found exclusively in the corm material of “Bluggoe” that had been fed on by the weevils. Full article

(This article belongs to the Special Issue Plant Flavonoids)

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993 KiB

Open AccessReview

The Role of Flavonoids in Nodulation Host-Range Specificity: An Update

by Cheng-Wu Liu and Jeremy D. Murray

Plants 2016, 5(3), 33; https://doi.org/10.3390/plants5030033 - 11 Aug 2016

Cited by 200 | Viewed by 11693

Abstract

Flavonoids are crucial signaling molecules in the symbiosis between legumes and their nitrogen-fixing symbionts, the rhizobia. The primary function of flavonoids in the interaction is to induce transcription of the genes for biosynthesis of the rhizobial signaling molecules called Nod factors, which are [...] Read more.

Flavonoids are crucial signaling molecules in the symbiosis between legumes and their nitrogen-fixing symbionts, the rhizobia. The primary function of flavonoids in the interaction is to induce transcription of the genes for biosynthesis of the rhizobial signaling molecules called Nod factors, which are perceived by the plant to allow symbiotic infection of the root. Many legumes produce specific flavonoids that only induce Nod factor production in homologous rhizobia, and therefore act as important determinants of host range. Despite a wealth of evidence on legume flavonoids, relatively few have proven roles in rhizobial infection. Recent studies suggest that production of key “infection” flavonoids is highly localized at infection sites. Furthermore, some of the flavonoids being produced at infection sites are phytoalexins and may have a role in the selection of compatible symbionts during infection. The molecular details of how flavonoid production in plants is regulated during nodulation have not yet been clarified, but nitrogen availability has been shown to play a role. Full article

(This article belongs to the Special Issue Plant Flavonoids)

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1632 KiB

Open AccessMeeting Report

Evaluating the Role of Seed Treatments in Canola/Oilseed Rape Production: Integrated Pest Management, Pollinator Health, and Biodiversity

by Gregory Sekulic and Curtis B. Rempel

Plants 2016, 5(3), 32; https://doi.org/10.3390/plants5030032 - 03 Aug 2016

Cited by 22 | Viewed by 8163

Abstract

The use patterns and role of insecticide seed treatments, with focus on neonicotinoid insecticides, were examined for canola/oilseed rape production in Canada and the EU. Since nearly all planted canola acres in Western Canada and, historically, a majority of planted oilseed acres in [...] Read more.

The use patterns and role of insecticide seed treatments, with focus on neonicotinoid insecticides, were examined for canola/oilseed rape production in Canada and the EU. Since nearly all planted canola acres in Western Canada and, historically, a majority of planted oilseed acres in the EU, use seed treatments, it is worth examining whether broad use of insecticidal seed treatments (IST) is compatible with principles of integrated pest management (IPM). The neonicotinoid insecticide (NNI) seed treatment (NNI ST) use pattern has risen due to effective control of several early season insect pests, the most destructive being flea beetles (Phyllotreta sp.). Negative environmental impact and poor efficacy of foliar applied insecticides on flea beetles led growers to look for better alternatives. Due to their biology, predictive models have been difficult to develop for flea beetles, and, therefore, targeted application of seed treatments, as part of an IPM program, has contributed to grower profitability and overall pollinator success for canola production in Western Canada. Early evidence suggests that the recent restriction on NNI may negatively impact grower profitability and does not appear to be having positive impact on pollinator health. Further investigation on impact of NNI on individual bee vs. hive health need to be conducted. Predictive models for flea beetle emergence/feeding activity in canola/oilseed rape need to be developed, as broad acre deployment of NNI seed treatments may not be sustainable due to concerns about resistance/tolerance in flea beetles and other pest species. Full article

(This article belongs to the Special Issue Selected/Extended Full Papers of 14th International Rapeseed Congress)

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1100 KiB

Open AccessArticle

Blackleg (Leptosphaeria maculans) Severity and Yield Loss in Canola in Alberta, Canada

by Sheau-Fang Hwang, Stephen E. Strelkov, Gary Peng, Hafiz Ahmed, Qixing Zhou and George Turnbull

Plants 2016, 5(3), 31; https://doi.org/10.3390/plants5030031 - 20 Jul 2016

Cited by 36 | Viewed by 8334

Abstract

Blackleg, caused by Leptosphaeria maculans, is an important disease of oilseed rape (Brassica napus L.) in Canada and throughout the world. Severe epidemics of blackleg can result in significant yield losses. Understanding disease-yield relationships is a prerequisite for measuring the agronomic [...] Read more.

Blackleg, caused by Leptosphaeria maculans, is an important disease of oilseed rape (Brassica napus L.) in Canada and throughout the world. Severe epidemics of blackleg can result in significant yield losses. Understanding disease-yield relationships is a prerequisite for measuring the agronomic efficacy and economic benefits of control methods. Field experiments were conducted in 2013, 2014, and 2015 to determine the relationship between blackleg disease severity and yield in a susceptible cultivar and in moderately resistant to resistant canola hybrids. Disease severity was lower, and seed yield was 120%–128% greater, in the moderately resistant to resistant hybrids compared with the susceptible cultivar. Regression analysis showed that pod number and seed yield declined linearly as blackleg severity increased. Seed yield per plant decreased by 1.8 g for each unit increase in disease severity, corresponding to a decline in yield of 17.2% for each unit increase in disease severity. Pyraclostrobin fungicide reduced disease severity in all site-years and increased yield. These results show that the reduction of blackleg in canola crops substantially improves yields. Full article

(This article belongs to the Special Issue Selected/Extended Full Papers of 14th International Rapeseed Congress)

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3445 KiB

Open AccessArticle

Comparison between Canadian Canola Harvest and Export Surveys

by Véronique J. Barthet

Plants 2016, 5(3), 30; https://doi.org/10.3390/plants5030030 - 20 Jul 2016

Cited by 4 | Viewed by 4332

Abstract

Parameters, such as oil, protein, glucosinolates, chlorophyll content and fatty acid composition, were determined using reference methods for both harvest survey samples and Canadian Canola exports. Canola harvest survey and export data were assessed to evaluate if canola harvest survey data can be [...] Read more.

Parameters, such as oil, protein, glucosinolates, chlorophyll content and fatty acid composition, were determined using reference methods for both harvest survey samples and Canadian Canola exports. Canola harvest survey and export data were assessed to evaluate if canola harvest survey data can be extrapolated to predict the quality of the Canadian canola exports. There were some differences in some measured parameters between harvest and export data, while other parameters showed little difference. Protein content and fatty acid composition showed very similar data for harvest and export averages. Canadian export data showed lower oil content when compared to the oil content of harvest survey was mainly due to a diluting effect of dockage in the export cargoes which remained constant over the years (1.7% to 1.9%). Chlorophyll was the least predictable parameter; dockage quality as well as commingling of the other grades in Canola No. 1 Canada affected the chlorophyll content of the exports. Free fatty acids (FFA) were also different for the export and harvest survey. FFA levels are affected by storage conditions; they increase during the shipping season and, therefore, are difficult to predict from their harvest survey averages. Full article

(This article belongs to the Special Issue Selected/Extended Full Papers of 14th International Rapeseed Congress)

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24745 KiB

Open AccessArticle

Variations in the Life Cycle of Anemone patens L. (Ranunculaceae) in Wild Populations of Canada

by Vladimir Kricsfalusy

Plants 2016, 5(3), 29; https://doi.org/10.3390/plants5030029 - 30 Jun 2016

Cited by 10 | Viewed by 10258

Abstract

Based on a study of a perennial herb Anemone patens L. (Ranunculaceae) in a variety of natural habitats in Saskatchewan, Canada, eight life stages (seed, seedling, juvenile, immature, vegetative, generative, subsenile, and senile) are distinguished and characterized in detail. The species ontogenetic growth [...] Read more.

Based on a study of a perennial herb Anemone patens L. (Ranunculaceae) in a variety of natural habitats in Saskatchewan, Canada, eight life stages (seed, seedling, juvenile, immature, vegetative, generative, subsenile, and senile) are distinguished and characterized in detail. The species ontogenetic growth patterns are investigated. A. patens has a long life cycle that may last for several decades which leads to the formation of compact clumps. The distribution and age of clumps vary substantially in different environments with different levels of disturbance. The plant ontogeny includes the regular cycle with reproduction occurring through seeds. There is an optional subsenile vegetative disintegration at the end of the life span. The following variations in the life cycle of A. patens are identified: with slower development in young age, with an accelerated development, with omission of the generative stage, with retrogression to previous life stages in mature age, and with vegetative dormancy. The range of variations in the life cycle of A. patens may play an important role in maintaining population stability in different environmental conditions and management regimes. Full article

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