Wijewardana Chathurika, Henry W Brien, Gao Wei, Reddy K Raja
Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
USDA-UV-B Monitoring Network, Natural Resource Ecology Lab., Colorado State University, Fort Collins, CO 80523, USA.
J Photochem Photobiol B. 2016 Jul;160:198-209. doi: 10.1016/j.jphotobiol.2016.04.004. Epub 2016 Apr 14.
Crop growth and development are highly responsive to global climate change components such as elevated carbon dioxide (CO2), drought, and ultraviolet-B (UV-B) radiation. Plant tolerance to these environmental stresses comprises its genetic potential, physiological changes, metabolism, and signaling pathways. An inclusive understanding of morphological, physiological, and biochemical responses to these abiotic stresses is imperative for the development of stress tolerant varieties for future environments. The objectives of this study were to characterize the changes in vegetative and physiological traits in maize hybrids in their response to multiple environmental factors of (CO2) [400 and 750μmolmol(-1) (+(CO2)], irrigation treatments based evapotranspiration (ET) [100 and 50% (-ET)], and UV-B radiation [0 and 10kJm(-2)d(-1) (+UV-B)] and to identify the multiple stress tolerant hybrids aid in mitigating projected climate change for shaping future agriculture. Six maize hybrids (P1498, DKC 65-81, N75H-GTA, P1319, DKC 66-97, and N77P-3111) with known drought tolerance variability were grown in eight sunlit, controlled environment chambers in which control treatment consisted of 400μmolmol(-1) [CO2], 100% ET-based irrigation, and 0kJ UV-B. Plants grown at +UV-B alone or combination with 50% ET produced shorter plants and smaller leaf area while elevated CO2 treatments ameliorated the damaging effects of drought and higher UV-B levels on maize hybrids. Plant height, leaf area, total dry matter chlorophyll, carotenoids, and net photosynthesis measured were increased in response to CO2 enrichment. Total stress response index (TSRI) for each hybrid, developed from the cumulative sum of response indices of vegetative and physiological parameters, varied among the maize hybrids. The hybrids were classified as tolerant (P1498), intermediate (DKC 65-81, N75H-GTA, N77P-3111) and sensitive (P1319 and DKC 66-97) to multiple environmental stresses. The positive correlation between TSRI and vegetative and physiological index developed in this study demonstrates that a combination of vegetative and physiological traits is an effective screening tool to identify germplasm best suited to cope with future changing climates. Furthermore, the tolerant hybrids identified in this study indicate that the possibility of cultivar selection for enhanced agronomic performance and stability in a water limited environment with higher UV-B, anticipated to occur in future climates.
作物生长发育对全球气候变化因素高度敏感，如二氧化碳（CO₂）浓度升高、干旱和紫外线B（UV-B）辐射。植物对这些环境胁迫的耐受性包括其遗传潜力、生理变化、新陈代谢和信号传导途径。全面了解对这些非生物胁迫的形态、生理和生化反应，对于培育适应未来环境的耐胁迫品种至关重要。本研究的目的是表征玉米杂交种在响应多种环境因素时营养和生理性状的变化，这些环境因素包括（CO₂）[400和750μmolmol⁻¹（+（CO₂）]、基于蒸发散（ET）的灌溉处理[100%和50%（-ET）]以及UV-B辐射[0和10kJm⁻²d⁻¹（+UV-B）]，并鉴定多胁迫耐受性杂交种，以帮助缓解预计的气候变化，塑造未来农业。六个已知耐旱性差异的玉米杂交种（P1498、DKC 65-81、N75H-GTA、P1319、DKC 66-97和N77P-3111）种植在八个有阳光的可控环境箱中，对照处理包括400μmolmol⁻¹[CO₂]、基于100%ET的灌溉和0kJ UV-B。单独在+UV-B条件下或与50%ET组合条件下生长的植株较矮，叶面积较小，而CO₂浓度升高处理减轻了干旱和较高UV-B水平对玉米杂交种的损害作用。测量的株高、叶面积、总干物质、叶绿素、类胡萝卜素和净光合作用因CO₂浓度升高而增加。根据营养和生理参数响应指数的累积总和得出的每个杂交种的总胁迫响应指数（TSRI）在玉米杂交种之间有所不同。这些杂交种被分类为对多种环境胁迫耐受（P1498）、中等耐受（DKC 65-81、N75H-GTA、N77P-3111）和敏感（P1319和DKC 66-97）。本研究中TSRI与营养和生理指标之间的正相关表明，营养和生理性状的组合是识别最适合应对未来气候变化种质的有效筛选工具。此外，本研究中鉴定出的耐受杂交种表明，在未来气候中预计会出现的高UV-B且水分有限的环境中，有可能选择具有更高农艺性能和稳定性的品种。
