乙烯利对核桃叶片衰老和光合同化产物的影响

Effects of Ethephon on Senescence and Photo-contracted Products of Walnut Leaves

以嫁接四年生‘农核1号’核桃为试材,采用秋季叶面喷施乙烯利的方法,研究乙烯利对叶绿素、渗透调节物质和光合同化产物的影响,以期为有效预防深秋初冬低温霜冻提供参考依据。结果表明:采样后期,0.25 mg·L^(-1)乙烯利叶绿素含量较对照提高7.77%,0.50 mg·L^(-1)和1.00 mg·L^(-1)乙烯利较对照极显著降低9.56%和35.84%(P<0.01),0.50 mg·L^(-1)和1.00 mg·L^(-1)乙烯利丙二醛(MDA)含量分别较对照极显著提高17.40%和51.83%(P<0.01);0.50 mg·L^(-1)和1.00 mg·L^(-1)乙烯利可使采样后期脯氨酸含量较对照极显著提高11.88%和58.70%(P<0.01);净光合速率分别较对照降低10.19%、15.05%和20.02%,淀粉含量较对照极显著降低10.43%、26.68%和24.76%(P<0.01);可溶性糖含量较对照极显著降低11.18%、15.79%和20.60%(P<0.01)。因此,喷施乙烯利可以降低衰老期叶片叶绿素含量和净光合速率,减少光合同化产物淀粉含量的积累,加速叶片衰老,降低还原糖和可溶性糖含量,其中0.50 mg·L^(-1)和1.00 mg·L^(-1)乙烯利可以提高叶片MDA含量和脯氨酸含量,分别较对照提前5 d和13 d落叶。

Taking grafted four-year-old walnut ‘Nonghe No.1’ as test material, the effects of ethephon on chlorophyll, osmotic regulation substances and photosynthetic products were studied by spraying ethephon on the leaves of walnut in autumn, in order to provide reference for effective prevention of cold frost in late autumn and early winter.The results showed that at the later stage of sampling, chlorophyll content of spraying 0.25 mg·L^(-1)ethephon increased by 7.77%,but spraying 0.50 mg·L^(-1)and 1.00 mg·L^(-1)ethephon significantly decreased by 9.56% and 35.84% compared with the control(P<0.01).However, the MDA content of spraying 0.50 mg·L^(-1)and 1.00 mg·L^(-1)ethephon was significantly increased by 17.40% and 51.83%,respectively(P<0.01).And the proline content of spraying 0.50 mg·L^(-1)and 1.00 mg·L^(-1)was significantly increased by 11.88% and 58.70%(P<0.01).Compared with the control, net photosynthetic rate(Pn) of spraying three treatments decreased by 10.19%,15.05% and 20.02%,respectively.The starch content significantly decreased by 10.43%,26.68% and 24.76%(P<0.01).Soluble sugar content was significantly reduced by 11.18%,15.79% and 20.60%(P<0.01).Therefore, ethephon sprayed at leaf aging stage can not only reduce chlorophyll content, Pn and accumulation of starch content, but also accelerate leaf senescence.It also reduced reducing sugar and soluble sugar contents, ethephon at 0.50 mg·L^(-1)and 1.00 mg·L^(-1)could increase MDA content and proline content of leaves, and leaves were defoliated 5 days and 13 days earlier than the control, respectively.