外源亚精胺对干旱胁迫下谷子幼苗光合作用及碳水化合物积累的影响

Effects of Exogenous Spermidine on Photosynthesis and Carbohydrate Accumulation in Foxtail Millet( Setaria italica) Seedlings under Drought Stress

以干旱敏感的谷子品种‘狼尾巴’为试验材料,在营养液栽培模式下,采用20%聚乙二醇(PEG-6000)模拟干旱,研究了外源亚精胺(Spd)对干旱胁迫下谷子幼苗光合特性、碳水化合物积累以及蔗糖、淀粉合成关键酶活性的影响。结果表明,干旱胁迫显著降低了谷子幼苗光合作用和碳水化合物积累,抑制植株的发育,而外源Spd处理能在一定程度上逆转这种效果,0.1mmol/L亚精胺处理后,谷子幼苗光合参数、叶绿素荧光参数均比干旱胁迫处理显著升高,同时蔗糖磷酸合成酶、淀粉合成酶等酶活性升高,并最终促进了蔗糖、可溶性总糖以及淀粉等碳水化合物的积累,缓解了干旱胁迫对谷子幼苗生长发育的抑制。以上结果表明,干旱胁迫下,外源Spd能缓解叶片气孔的关闭,促进植株对CO2的吸收,提高植物的光合作用和碳水化合物积累能力,并最终提高了谷子幼苗的抗旱性。

Drought sensitive cuhivar＇ Wolf tail＇was used as test material, effects of exogenous spermidine （Spd）on photosynthesis, carbohydrate accumulation and activities of carbohydrate synthesis enzymes in foxtail millet seedlings were studied. The results showed that drought stress caused a significant decrease in photosynthetic parameters and carbohydrate accumulation, and finally reduced the plant growth and biomass of seedlings. Compared with the drought treatment, exogenous Spd aggravated the detrimental effects of drought stress on plant growth and biomass production. Application of Spd to drought stress nutrient solution increased photosynthetic and chlorophyll fluorescence parameters, activities of sucrose phosphorus synthetase （ SPS）, sucrose synthase （ SS, the direction of synthesis）, ADP glucose pyrophosphorylase （AGPP）, and starchy synthase （SSS）, essential enzymes of carbohydrate metabolism, and consequently increased the accumulation of sucrose and starch. These results indicated that exogenous Spd could improve drought tolerance of foxtail millet seedlings by preventing stoma closure, stimulating CO2 uptake, increasing photosynthetic and chlorophyll fluorescence parameters, improving carbohydrate accumulation ability and finally improve the drought tolerance of foxtail millet seedlings.