油菜素内酯对干旱胁迫下辣椒叶片活性氧代谢的影响

EFFECTS OF BRASSINOLIDE ON ACTIVE OXYGEN METABOLISM IN PEPPER LEAVES UNDER DROUGHT STRESS

以辣椒品种湘研6号为材料,研究了干旱胁迫下0.05mg/L的油菜素内酯(BR)对辣椒叶片活性氧代谢的影响。研究表明,干旱胁迫显著抑制了辣椒叶片净光合速率(Pn)、PSII光合电子传递量子效率(ΦPSII)和光化学猝灭系数(qP),虽然干旱胁迫诱导了非光化学猝灭系数(NPQ)以及超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和过氧化物酶(POD)的酶活性,但仍导致叶片PSII最大光化学效率(Fv/Fm)的下降和过氧化氢(H2O2)和丙二醛(MDA)含量的大幅上升;油菜素内酯有效地促进了干旱胁迫下辣椒叶片Pn、ΦPSII、qP和NPQ的增强,也显著增强了SOD、APX、CAT和POD的酶活性,从而减轻了干旱胁迫所导致的Fv/Fm的下降和H2O2和MDA含量的增加。结果表明,油菜素内酯可通过增强碳同化和热耗散能力,并诱导抗氧化酶活性的增加,以促进作物的抗旱性。

In order to investigate the effects of brassinosteroid（BR） on active oxygen metabolism in pepper leave under drought stress,the pepper cultivar,Xiangyan No.6 was used as the material.In this study,drought significantly inhibited Pn,ΦPSII,qP,however,induced the increase of NPQ and activities of antioxidant enzymes（SOD,APX,CAT and POD）.Then drought deceased Fv/Fm and increased the contents of H2O2 and MDA.0.05 mg/L BR can markedly increased Fv/Fm and decreased the content of H2O2 and MDA.BR significantly alleviated drought-inhibition of Pn,ΦPSII,qP and NPQ.BR also increased the activities of SOD,APX,CAT and POD.Taken together,the results suggested that BR treatment can enhance the drought-tolerance of pepper by improved CO2 assimilation,dissipation of excitation energy as heat from the light harvesting complex in PSII and antioxidant enzymes activities.