分类： 生物学 >> 生态学 提交时间： 2024-01-12 合作期刊: 《干旱区科学》
摘要： Gross primary productivity (GPP) of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought. Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks, aiding efforts to mitigate the detrimental effects of climate change. In this study, we utilized the precipitation and temperature data from the Climatic Research Unit, the standardized precipitation evapotranspiration index (SPEI), the standardized precipitation index (SPI), and the simulated vegetation GPP using the eddy covariance-light use efficiency (EC-LUE) model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 19822018. The main findings indicated that vegetation GPP decreased in 50.53% of the plateau, mainly in its northern and northeastern parts, while it increased in the remaining 49.47% area. Specifically, meadow steppe (78.92%) and deciduous forest (79.46%) witnessed a significant decrease in vegetation GPP, while alpine steppe (75.08%), cropland (76.27%), and sandy vegetation (87.88%) recovered well. Warming aridification areas accounted for 71.39% of the affected areas, while 28.53% of the areas underwent severe aridification, mainly located in the south and central regions. Notably, the warming aridification areas of desert steppe (92.68%) and sandy vegetation (90.24%) were significant. Climate warming was found to amplify the sensitivity of coniferous forest, deciduous forest, meadow steppe, and alpine steppe GPP to drought. Additionally, the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased. The cumulative effect of drought on vegetation GPP persisted for 3.008.00 months. The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.
分类： 生物学 >> 植物学 >> 植物生态学和植物地理学 提交时间： 2016-05-30
摘要： Flood and drought are the two most prevalent abiotic stresses causing major yield reduction globally. In the last decade, molecular mechanisms of flood tolerance in rice have been revealed with successful release of flash flood-tolerant varieties to farmers. However, despite extensive research, the breakthrough of drought tolerance is still to come. In this review, we have examined the distribution and population types of drought-and flood-tolerant rice accessions, synthesized recent progresses of flood and drought tolerance research, and proposed a hypothesis that the molecular mechanisms of both drought and flood tolerance may be regulated by cross-talked pathways and coexist in aus subpopulation.We conclude that it is the time to mine the key regulator(s) of drought tolerance through de novo assembly of drought-tolerant aus landrace(s) with other molecular approaches and develop drought-tolerant rice using genome manipulation weaponry.
分类： 生物学 >> 植物学 >> 植物生物化学、植物生物物理学 提交时间： 2016-05-04
摘要： Drought stress has adverse impacts on plant production and productivity. MicroRNAs (miRNAs) are one class of noncoding RNAs regulating gene expression post-transcriptionally. In this study, we employed small RNA and degradome sequencing to systematically investigate the tissue-specific miRNAs responsible to drought stress, which are understudied in tomato. For this purpose, root and upground tissues of two different drought-responsive tomato genotypes (Lycopersicon esculentum as sensitive and L. esculentum var. cerasiforme as tolerant) were subjected to stress with 5% polyethylene glycol for 7days. A total of 699 conserved miRNAs belonging to 578 families were determined and 688 miRNAs were significantly differentially expressed between different treatments, tissues and genotypes. Using degradome sequencing, 44 target genes were identified associated with 36 miRNA families. Drought-related miRNAs and their targets were enriched functionally by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Totally, 53 miRNAs targeted 23 key drought stress- and tissue development-related genes, including DRP (dehydration-responsive protein), GTs (glycosyltransferases), ERF (ethylene responsive factor), PSII (photosystem II) protein, HD-ZIP (homeodomain-leucine zipper), MYB and NAC-domain transcription factors. miR160, miR165, miR166, miR171, miR398, miR408, miR827, miR9472, miR9476 and miR9552 were the key miRNAs functioning in regulation of these genes and involving in tomato response to drought stress. Additionally, plant hormone signal transduction pathway genes were differentially regulated by miR169, miR172, miR393, miR5641, miR5658 and miR7997 in both tissues of both sensitive and tolerant genotypes. These results provide new insight into the regulatory role of miRNAs in drought response with plant hormone signal transduction and drought-tolerant tomato breeding.
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