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[目的]本文旨在探讨NO对水稻孕穗期干旱胁迫下叶片光合机构损伤的缓解作用。[方法]以‘早玉香粳’为试验材料,采用盆栽,在孕穗期设4个处理:正常水分管理+喷施清水(用WT表示);正常水分管理+喷施100μmol·L~(-1)硝普钠(SNP,sodium nitroprusside)(W100);干旱胁迫+喷施清水(DS);干旱胁迫+喷施100μmol·L~(-1)SNP(D100)。在喷施SNP后1、4、7、10 d取样,测定水稻光合作用,叶绿素荧光动力学参数,抗氧化酶[超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)]活性,丙二醛(MDA)含量,超氧阴离子(O_2~)产生速率和过氧化氢(H_2O_2)含量以及产量等指标。[结果]与正常水分管理相比,干旱胁迫下水稻SOD、CAT、POD活性显著升高,一定程度上可以抑制MDA积累;H_2O_2含量、O_2~产生速率显著增加并随着干旱胁迫加剧持续增加;净光合速率(P_n)、气孔导度(Gs)和蒸腾速率(Tr)随着干旱胁迫加剧,呈下降趋势;胞间CO2浓度(Ci)呈先下降后上升的趋势;叶绿素荧光参数最小荧光(Fo)、非荧光淬灭(NPQ)显著上升,并随着干旱的持续加剧上升;最大光化学效率(Fv/Fm)、光化学淬灭(q P)显著下降,并随着干旱的持续加剧下降,最终导致水稻产量显著下降。叶面喷施NO,短期内降低了水稻P_n,但提高了水稻干旱胁迫时叶片抗氧化酶活性,其中H_2O_2、MDA含量以及O_2~产生速率较干旱喷水处理降低了14.4%、18.3%、14.38%;同时诱导气孔关闭,继而降低蒸腾速率,减少水分过度消耗;缓解了Fo的增加和Fv/Fm、q P的下降,并进一步增加了NPQ,加快复水后光合机构功能修复,最终产量较干旱胁迫下提高了21.0%。[结论]NO对水稻孕穗期干旱胁迫下光合机构具有明显的保护作用,并促进复水后光合作用的恢复,减轻了干旱造成的产量损失。
[Objective] The aim of this paper was to investigate the alleviating effect of NO on the damage of photosynthetic apparatus in leaves under drought stress at the booting stage of rice. [Method] With ’Zaoyujingjing’ as tested material, potted plants were used and four treatments were set at booting stage: normal water management + spraying water (WT); normal water management + spraying 100μmol·L ~ 1) sodium nitroprusside (W100); drought stress + sprayed water (DS); drought stress + 100 μmol·L -1 SNP (D100). The photosynthesis, chlorophyll fluorescence kinetics parameters, antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), peroxides (POD) activity, malondialdehyde (MDA) content, superoxide anion (O_2 ~ ) production rate and hydrogen peroxide (H_2O_2) content and yield. [Result] Compared with normal water management, the activity of SOD, CAT and POD of rice under drought stress was significantly increased, which could inhibit the accumulation of MDA to some extent. The content of H 2 O 2 and the production rate of O 2 ~ 显 increased significantly with the increase of drought stress (P n), stomatal conductance (Gs) and transpiration rate (Tr) decreased with the increase of drought stress; the intercellular CO2 concentration (Ci) decreased first and then increased; the chlorophyll fluorescence minimum fluorescence (Fv / Fm) and photochemical quenching (q P) decreased significantly with the increasing of non-fluorescence quenching (NPQ) Eventually leading to a significant drop in rice production. Leaf NO application reduced P_n in rice in a short time, but increased antioxidant enzyme activity in leaves under drought stress. H_2O_2, MDA content and O_2 ~ production rate decreased by 14.4% and 18.3%, respectively, 14.38%. At the same time, the stomatal closure was induced, and then the transpiration rate was decreased and the excessive water consumption was reduced. The increase of Fo and the decrease of Fv / Fm and q P were alleviated and the NPQ was further increased. Compared with the drought stress increased 21.0%. [Conclusion] NO had a significant protective effect on photosynthetic apparatus under drought stress at booting stage of rice and promoted the recovery of photosynthesis after rewatering, and reduced the yield loss caused by drought.