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【目的】初步评价湖北海棠(Malus hupehensis)耐涝性,并从色素含量和叶绿素荧光动力学角度分析其耐涝机理。【方法】通过人工模拟淹水胁迫,对淹水胁迫过程中湖北海棠生长、叶片外观及叶绿素快相荧光动力学特征进行分析。【结果】(1)淹水处理显著抑制湖北海棠的生长,但淹水30~200 d苗木成活率仍为100%。(2)淹水后叶色转红,叶绿素与类胡萝卜素和花青素的相对含量比值(Chl/(Car+Anth))显著下降。(3)叶绿素荧光动力学结果表明,处理叶片在O相的初始荧光Fo显著高于对照,在P相的最大荧光Fm显著低于对照,且淹水后在J相处的可变荧光Vj升幅(3.4%~9.0%)大于K相处的可变荧光Vk(3.8%~11.6%)。随着淹水时间延长,叶片单位面积的反应中心数目(RC/CSm)和PSⅡ电子受体库容量(Sm)显著降低,电子由QA向QB的传递过程受抑制,导致PSⅡ向PSⅠ的电子传递能力降低(Ψo和φRo),最终表现为光合性能指数(PItotal)受到显著抑制。然而,叶片的DIo/CSm显著递增。【结论】淹水胁迫显著抑制湖北海棠生长,但并不致死,因此可认为其具备一定的耐水淹能力。虽然淹水对湖北海棠叶片PSⅡ电子受体侧的影响大于供体测,但叶片可通过增加热耗散比及Car和Anth比例来降低激发能的产生以及过剩激发能的伤害,从而提高其耐水淹能力。
【Objective】 To evaluate the waterlogging tolerance of Malus hupehensis and to analyze its waterlogging tolerance mechanism from the aspects of pigment content and chlorophyll fluorescence kinetics. 【Method】 Fluorescence kinetics characteristics of growth, leaf appearance and fast chlorophyll fluorescence of Begonia in the process of waterlogging were analyzed by artificial simulated flooding stress. 【Result】 (1) The flooding treatment significantly inhibited the growth of Begonia cambogia, but the survival rate of seedlings remained 100% after flooding for 30 ~ 200 days. (2) Leaf color turned red after flooding, and the relative content of chlorophyll, carotenoid and anthocyanin (Chl / (Car + Anth)) decreased significantly. (3) The chlorophyll fluorescence kinetics results showed that the initial fluorescence Fo of the treated leaves in O phase was significantly higher than that of the control, the maximum fluorescence Fm in P phase was significantly lower than that of the control, and the variable fluorescence Vj in J phase after flooding was increased 3.4% ~ 9.0%) was greater than the K-phase variable fluorescence Vk (3.8% ~ 11.6%). With the prolongation of flooding time, the number of reaction centers per unit area (RC / CSm) and the PS Ⅱ electron acceptor volume (Sm) were significantly decreased, and the electron transfer from QA to QB was inhibited, resulting in the electron transfer of PSⅡ to PSⅠ The ability to decrease (Ψo and φRo) eventually led to a significant suppression of the PItotal. However, DIo / CSm of leaves increased significantly. 【Conclusion】 The waterlogging significantly inhibited the growth of Begoniaceae in Hubei Province, but it was not lethal. Therefore, it is considered that it has certain resistance to flooding. Although the effect of flooding on PS Ⅱ electron acceptor side of Begonia officinalis is greater than that of donor, the leaf can increase its heat dissipation ratio and Car and Anth ratio to reduce the excitation energy and the damage of excess excitation energy ability.