干旱胁迫下二氢卟吩铁对棉花光合与抗氧化特性的影响

Effects of iron chlorine e6 on photosynthetic characteristics and antioxidant properties of cotton under soil drought

【目的】明确新型植物生长调节剂二氢卟吩铁(iron chlorine e6,ICE6)提高棉花抗旱性的生理机制。【方法】于2021、2022年在防雨棚内进行池栽试验,以早熟棉花品种中棉所425为材料,研究初花期喷施ICE6对干旱胁迫下(连续14 d不灌水)棉花光合与抗氧化特性、生物量及产量的影响。【结果】与正常灌水相比,干旱胁迫下棉花叶片净光合速率(net photosynthetic rate,Pn)、气孔导度、胞间CO_(2)浓度及蒸腾速率分别降低41.5%、37.2%、11.1%、23.1%(2021年)和17.2%、21.7%、9.4%、22.7%(2022年),干旱胁迫下喷施ICE6后则分别降低31.3%、18.6%、4.4%、15.4%(2021年)和6.6%、3.7%、4.2%、11.0%(2022年)。喷施ICE6减缓了干旱造成的棉花光合性能的降低,缩小了干旱胁迫下棉花叶片光饱和点时Pn的降幅,增大了光补偿点时Pn的降幅,显著降低了暗呼吸速率,减缓CO_(2)饱和点时Pn的降幅。干旱胁迫下喷施ICE6能增强叶片超氧化物歧化酶、过氧化物酶及过氧化氢酶活性,降低丙二醛含量。最终,喷施ICE6缩小了干旱胁迫下棉花的生物量及籽棉产量的降幅,但对正常灌水处理的棉花光合作用、抗氧化能力、生物量与籽棉产量影响较小。【结论】干旱胁迫下,喷施ICE6可以显著增强棉花对弱光的利用,减轻光抑制、减弱暗呼吸,增强棉花的抗氧化能力,这是在干旱胁迫下外源ICE6维持棉花生物量、保持籽棉产量水平的生理基础。

[Objective]This study was aimed to clarify the physiological mechanism of a new plant growth regulator iron chlorine e6(ICE6)in improving cotton drought tolerance under soil drought stress at the early flowering stage.[Method]In 2021-2022,the short-season cotton variety CCRI 425 were planted in pools with rainproof shelter,and ICE6 was sprayed on leaf at initial flowering stage to evaluate the effects on the photosynthesis,antioxidation,biomass,and yield under drought stress(without watering in 14 d),taking well water conditions as control(CK).[Result]Compared with the well water conditions,the net photosynthetic rate Pn,stomatal conductance,intercellular CO_(2)concentration,and transpiration rate of cotton leaves under drought stress decreased by 41.5%,37.2%,11.1%,23.1%in 2021 and 17.2%,21.7%,9.4%,22.7%in 2022,respectively,while decreased by 31.3%,18.6%,4.4%,15.4%in 2021 and 6.6%,3.7%,4.2%,11.0%in 2022 with spraying ICE6 under drought stress.This indicated that exogenous ICE6 can alleviate the reduction of the photosynthesis caused by drought.ICE6 also alleviated the reduction of the Pn at light saturation point and increased the reduction of the Pn at light compensation point,and significantly decreased the dark respiration rate under drought stress.ICE6 alleviated the reduction of the Pn at CO_(2)saturation point under drought.ICE6 increased the activities of superoxide dismutase,peroxidase,and hydrogen peroxide under drought,and decreasad the content of malondialdehyde.ICE6 alleviated the reduction of biomass and seed cotton yield under drought.However,ICE6 had less effect on the photosynthesis and antioxidation of cotton leaves,and the yield under well water conditions.[Conclusion]Under drought stress,ICE6 can significantly increase the photosynthesis of cotton leaves,improving the utilization of low light,and alleviating photoinhibition and dark respiration,and improve the antioxidation,which were the basis of alleviating the reduction of biomass and yield under drought stress.