scholarly journals Nitrogen deficiency regulates premature senescence by modulating flag leaf function, ROS homeostasis, and intercellular sugar concentration in rice during grain filling

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Shamsu Ado Zakari ◽  
Syed Hassan Raza Zaidi ◽  
Mustapha Sunusi ◽  
Kabiru Dawaki Dauda
Keyword(s):  
Grain Yield ◽  
Leaf Senescence ◽  
Flag Leaf ◽  
Grain Filling ◽  
Sugar Concentration ◽  
Premature Senescence ◽  
N Supply ◽  
Ros Homeostasis ◽  
N Assimilation ◽  
N Deficiency

Abstract Background Leaf senescence occurs in an age-dependent manner, but the rate and timing of leaf senescence may be influenced by various biotic and abiotic factors. In the course of stress, the function, composition, and different components of photosynthetic apparatus occur to be synthesized homogeneously or degraded paradoxically due to different senescence-related processes. Nitrogen (N) deficiency is one of the critical environmental factors that induce leaf senescence, and its incidence may curtail leaf photosynthetic function and markedly alter the genetic information of plants that might result in low grain yield. However, the physiological and genetic mechanism underlying N deficiency regulates premature senescence, and flag leaf function, ROS homeostasis, and intercellular sugar concentration in rice during grain filling are not well understood. In this paper, Zhehui7954 an excellent indica restorer line (wildtype) and its corresponding mutant (psf) with the premature senescence of flag leaves were used to study the effect of different N supplies in the alteration of physiological and biochemical components of flag leaf organ and its functions during grain filling. Results The results showed that the psf mutant appeared to be more susceptible to the varying N supply levels than WT. For instance, the psf mutant showed considerably lower Pn, Chl a, Chl b, and Car contents than its WT. N deficiency (LN) decreased leaves photosynthetic activities, N metabolites, but significantly burst O2•−, H2O2, and relative conductivity (R1/R2) concentrations, which was consistent with the expression levels of senescence-associated genes. Sucrose, glucose, and C/N ratio concentrations increased with a decrease in N level, which was closely associated with N and non-structural carbohydrate translocation rates. Increases in POD activity were positively linked with the senescence-related enhancement of ROS generation under LN conditions, whereas, SOD, CAT, and APX activities showed opposite trends. High N (HN) supply significantly inhibits the transcripts of carbohydrate biosynthesis genes, while N assimilation gene transcripts gradually increased along with leaf senescence. The psf mutant had a relatively higher grain yield under HN treatment than LN, while WT had a higher grain yield under MN than HN and LN. Conclusions This work revealed that the C/N ratio and ROS undergo a gradual increase driven by interlinking positive feedback, providing a physiological framework connecting the participation of sugars and N assimilation in the regulation of leaf senescence. These results could be useful for achieving a higher yield of rice production by appropriate N supply and plant senescence regulation.

Rate and duration of grain filling in relation to flag leaf senescence and grain yield in spring wheat (Triticum aestivum) exposed to different concentrations of ozone

2008 ◽  
Vol 110 (3) ◽  
pp. 366-375 ◽  
Author(s):  
Johanna Gelang ◽  
Håkan Pleijel ◽  
Ebe Sild ◽  
Helena Danielsson ◽  
Suhaila Younis ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Leaf Senescence ◽  
Spring Wheat ◽  
Flag Leaf ◽  
Grain Filling

Rate and duration of grain filling in relation to flag leaf senescence and grain yield in spring wheat (Triticum aestivum) exposed to different concentrations of ozone

2000 ◽  
Vol 110 (3) ◽  
pp. 366-375 ◽  
Author(s):  
Johanna Gelang ◽  
Hakan Pleijel ◽  
Ebe Sild ◽  
Helena Danielsson ◽  
Suhaila Younis ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Leaf Senescence ◽  
Spring Wheat ◽  
Flag Leaf ◽  
Grain Filling

scholarly journals Optimal Nitrogen Supply Ameliorates the Performance of Wheat Seedlings under Osmotic Stress in Genotype-Specific Manner

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 493 ◽  
Author(s):  
Tania Kartseva ◽  
Anelia Dobrikova ◽  
Konstantina Kocheva ◽  
Vladimir Alexandrov ◽  
Georgi Georgiev ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Stress Tolerance ◽  
Wheat Variety ◽  
Growth And Yield ◽  
Physiological Status ◽  
Wheat Seedlings ◽  
Modern Variety ◽  
N Supply ◽  
N Assimilation ◽  
N Deficiency

Strategies and coping mechanisms for stress tolerance under sub-optimal nutrition conditions could provide important guidelines for developing selection criteria in sustainable agriculture. Nitrogen (N) is one of the major nutrients limiting the growth and yield of crop plants, among which wheat is probably the most substantial to human diet worldwide. Physiological status and photosynthetic capacity of two contrasting wheat genotypes (old Slomer and modern semi-dwarf Enola) were evaluated at the seedling stage to assess how N supply affected osmotic stress tolerance and capacity of plants to survive drought periods. It was evident that higher N input in both varieties contributed to better performance under dehydration. The combination of lower N supply and water deprivation (osmotic stress induced by polyethylene glycol treatment) led to greater damage of the photosynthetic efficiency and a higher degree of oxidative stress than the individually applied stresses. The old wheat variety had better N assimilation efficiency, and it was also the one with better performance under N deficiency. However, when both N and water were deficient, the modern variety demonstrated better photosynthetic performance. It was concluded that different strategies for overcoming osmotic stress alone or in combination with low N could be attributed to differences in the genetic background. Better performance of the modern variety conceivably indicated that semi-dwarfing (Rht) alleles might have a beneficial effect in arid regions and N deficiency conditions.

Characterisation of grain yield and nitrogen level in relation to flag leaf senescence of wheat varieties

1986 ◽  
Vol 66 (3) ◽  
pp. 503-508 ◽  
Author(s):  
I. Ma. Martin del Molino ◽  
M. Ulloa ◽  
R. Martinez-Carrasco ◽  
P. Perez
Keyword(s):  
Grain Yield ◽  
Leaf Senescence ◽  
Flag Leaf ◽  
Nitrogen Level ◽  
Wheat Varieties

scholarly journals Effect of Heat Stress on Inter-relationship of Physiological and Biochemical Traits with Grain Yield in Wheat (Triticum aestivum L.)

2020 ◽  
pp. 19-29
Author(s):  
Amrita Kumari ◽  
R. D. Ranjan ◽  
Chandan Roy ◽  
Awadesh Kumar Pal ◽  
S. Kumar
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Flag Leaf ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Seedling Stage ◽  
Biochemical Traits ◽  
Highly Correlated ◽  
Complex Phenomena ◽  
Physiological And Biochemical

Heat stress, particularly the stress appears at the time of flowering to grain filling stages causing severe yield loss in wheat. Heat tolerance is complex phenomena that include adjustment in morphological, physiological and biochemical traits of the crop. Present investigation was carried out to understand the effect of terminal heat stress on different traits of wheat. The experiment was conducted in three dates of sowing as timely sown, late sown and very late sown to expose the crop to heat stress at later stages of the crop growth. Significant genetic variations for all the traits evaluated under three conditions indicated the presence of variability for the traits. Trait association analysis revealed that flag leaf chlorophyll content and MSI at seedling stage; MDA at reproductive stage had direct relationship with grain yield. While under very late sown condition MDA and RWC at seedling stages were found to be highly correlated with grain yield. It indicates that MDA, RWC at seedling stage and days to booting, days to milking plays important role in very late sown condition that can be used as selection criteria in breeding programme.

scholarly journals Mutation of ONAC096 Enhances Grain Yield by Increasing Panicle Number and Delaying Leaf Senescence during Grain Filling in Rice

2019 ◽  
Vol 20 (20) ◽  
pp. 5241 ◽  
Author(s):  
Kiyoon Kang ◽  
Yejin Shim ◽  
Eunji Gi ◽  
Gynheung An ◽  
Nam-Chon Paek
Keyword(s):  
Grain Yield ◽  
Leaf Senescence ◽  
Grain Filling ◽  
Pcr Analysis ◽  
Cytokinin Oxidase ◽  
Panicle Number ◽  
Reverse Transcription Quantitative Pcr ◽  
Dna Insertion ◽  
Upregulated Genes ◽  
Insertion Mutants

Exploring genetic methods to improve yield in grain crops such as rice (Oryza sativa) is essential to help meet the needs of the increasing population. Here, we report that rice ONAC096 affects grain yield by regulating leaf senescence and panicle number. ONAC096 expression increased rapidly in rice leaves upon the initiation of aging- and dark-induced senescence. Two independent T-DNA insertion mutants (onac096-1 and onac096-2) with downregulated ONAC096 expression retained their green leaf color during natural senescence in the field, thus extending their photosynthetic capacity. Reverse-transcription quantitative PCR analysis showed that ONAC096 upregulated genes controlling chlorophyll degradation and leaf senescence. Repressed OsCKX2 (encoding cytokinin oxidase/dehydrogenase) expression in the onac096 mutants led to a 15% increase in panicle number without affecting grain weight or fertility. ONAC096 mediates abscisic acid (ABA)-induced leaf senescence by upregulating the ABA signaling genes ABA INSENSITIVE5 and ENHANCED EM LEVEL. The onac096 mutants showed a 16% increase in grain yield, highlighting the potential for using this gene to increase grain production.

scholarly journals LPS1, Encoding Iron-Sulfur Subunit SDH2-1 of Succinate Dehydrogenase, Affects Leaf Senescence and Grain Yield in Rice

2020 ◽  
Vol 22 (1) ◽  
pp. 157
Author(s):  
Chun Li ◽  
Chuan-Qiang Liu ◽  
Hong-Shan Zhang ◽  
Cong-Ping Chen ◽  
Xiao-Rong Yang ◽  
...  
Keyword(s):  
Grain Yield ◽  
Succinate Dehydrogenase ◽  
Leaf Senescence ◽  
Photosynthetic Pigment ◽  
Plant Mitochondria ◽  
Mature Stage ◽  
Premature Senescence ◽  
Iron Sulfur ◽  
Nucleotide Mutation ◽  
Yield Formation

The iron-sulfur subunit (SDH2) of succinate dehydrogenase plays a key role in electron transport in plant mitochondria. However, it is yet unknown whether SDH2 genes are involved in leaf senescence and yield formation. In this study, we isolated a late premature senescence mutant, lps1, in rice (Oryza sativa). The mutant leaves exhibited brown spots at late tillering stage and wilted at the late grain-filling stage and mature stage. In its premature senescence leaves, photosynthetic pigment contents and net photosynthetic rate were reduced; chloroplasts and mitochondria were degraded. Meanwhile, lps1 displayed small panicles, low seed-setting rate and dramatically reduced grain yield. Gene cloning and complementation analysis suggested that the causal gene for the mutant phenotype was OsSDH2-1 (LOC_Os08g02640), in which single nucleotide mutation resulted in an amino acid substitution in the encoded protein. OsSDH2-1 gene was expressed in all organs tested, with higher expression in leaves, root tips, ovary and anthers. OsSDH2-1 protein was targeted to mitochondria. Furthermore, reactive oxygen species (ROS), mainly H2O2, was excessively accumulated in leaves and young panicles of lps1, which could cause premature leaf senescence and affect panicle development and pollen function. Taken together, OsSDH2-1 plays a crucial role in leaf senescence and yield formation in rice.

Heat stress in grain legumes during reproductive and grain-filling phases

2017 ◽  
Vol 68 (11) ◽  
pp. 985 ◽  
Author(s):  
Muhammad Farooq ◽  
Faisal Nadeem ◽  
Nirmali Gogoi ◽  
Aman Ullah ◽  
Salem S. Alghamdi ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Yield ◽  
Leaf Senescence ◽  
Management Strategies ◽  
Substantial Reduction ◽  
Grain Filling ◽  
Grain Legumes ◽  
Grain Legume ◽  
The Impact

Thermal stress during reproductive development and grain-filling phases is a serious threat to the quality and productivity of grain legumes. The optimum temperature range for grain legume crops is 10−36°C, above which severe losses in grain yield can occur. Various climatic models have simulated that the temperature near the earth’s surface will increase (by up to 4°C) by the end of this century, which will intensify the chances of heat stress in crop plants. The magnitude of damage or injury posed by a high-temperature stress mainly depends on the defence response of the crop and the specific growth stage of the crop at the time of exposure to the high temperature. Heat stress affects grain development in grain legumes because it disintegrates the tapetum layer, which reduces nutrient supply to microspores leading to premature anther dehiscence; hampers the synthesis and distribution of carbohydrates to grain, curtailing the grain-filling duration leading to low grain weight; induces poor pod development and fractured embryos; all of which ultimately reduce grain yield. The most prominent effects of heat stress include a substantial reduction in net photosynthetic rate, disintegration of photosynthetic apparatus and increased leaf senescence. To curb the catastrophic effect of heat stress, it is important to improve heat tolerance in grain legumes through improved breeding and genetic engineering tools and crop management strategies. In this review, we discuss the impact of heat stress on leaf senescence, photosynthetic machinery, assimilate translocation, water relations, grain quality and development processes. Furthermore, innovative breeding, genetic, molecular and management strategies are discussed to improve the tolerance against heat stress in grain legumes.

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