干旱胁迫对棉花生长发育和光合荧光参数的影响

为明确持续干旱胁迫对棉花生长发育、叶片水势、光合特性、荧光参数的影响,以‘新陆早57号’为试验材料,在土壤水分试验场内,设置3个水分处理（正常、轻度干旱、重度干旱）,研究不同干旱程度下棉花发育期、叶面积、干物质、产量、叶片水势、光合荧光参数的变化规律。结果表明：随着干旱胁迫时间的延长叶面积指数、光合物质积累量、籽棉产量、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、最大光化学效率(Fv/Fm)、实际光化学量子产量(Yield)、光化学猝灭系数(qP)呈下降趋势,叶片水势先下降后上升,非光化学猝灭系数(qN)则呈上升趋势,且随干旱程度的加剧而增加。经统计分析,干旱胁迫下Pn、Tr、Gs与对照差异显著(P<0.05)。干旱胁迫持续15天后,重度干旱胁迫下Yield、qP、qN与对照差异显著(P<0.05),轻度干旱差异不显著。Pn、Tr、Gs、Yield、qP、qN均能反映棉花叶片水分状况,但Yield、qP、qN更为敏感。

Response of Growth,Photosynthesis and Chlorophyll Fluorescence of Cotton to Drought Stress

To study the effects of drought stress on growth, photosynthesis and chlorophyll fluorescence of cotton, an experiment was conducted with 3 treatments: severe drought, mild drought and CK. Up-land cotton cultivar ‘Xinluzao 57’ was taken as the material and grown in soil moisture test site, and indicators including the development stages, LAI, biomass, seed cotton yield, water potential, photosynthesis and chlorophyll fluorescence were determined under different drought degrees. The results showed that: LAI, photosynthetic matter accumulation, seed cotton yield, net photosynthesis (Pn), transpiration rate (Tr), stomatal conductance (Gs), the maximal photochemical efficiency of PSⅡ in the dark (Fv/Fm), actual photochemical efficiency of PSⅡ in the light (Yield) and photochemical quenching coefficient (qP) presented downward trends along with the prolonging of the drought stress. Water potential increased at the early time, and then decreased, while non-photochemical quenching coefficient (qN) showed an increasing trend. Significant difference was found among Pn, Tr and Gs in drought treatment and CK (P＜0.05). Significant difference was also found between severe drought treatment and CK for Yield, qP and qN after 15 days of drought stress. Pn, Tr, Gs, Yield, qP and qN could be considered as indicators in cotton leaves, while Pn, Tr, Gs were more sensitive.