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以3年生自根‘巨峰’(Vitis vinifera‘Kyoho’)葡萄为试验材料,利用FMS-2荧光仪测定葡萄叶片的荧光指标,探讨干旱对葡萄叶片PSⅡ光化学效率以及光能分配的影响。结果表明,控水第1天,叶片过剩光能(Ex)便显著高于对照;控水第2天,叶片吸收的光能中应用于天线热耗散的份额(D)、非光化学猝灭(NPQ)显著高于对照,而用于光化学反应的份额(P)显著低于对照;控水第3天,叶片的天线转化效率(F′v/F′m)、实际光化学效率(ΦPSⅡ)显著低于对照,激发能在2个光系统间的分配不平衡性(β/α-1)显著提高;控水第4天叶片的光化学猝灭系数(qP)显著低于对照;最大光化学效率(Fv/Fm)在控水4d后显著低于对照。由此可见,在干旱胁迫下,植物叶片首先通过光能的分配来缓解过剩光能对光合机构的损伤;然后通过降低对光能的吸收来进行光保护;而后期水分胁迫加重,导致PSⅡ反应中心开放程度降低,光化学反应效率降低,最终发生光抑制。
Taking 3-year-old Vitis vinifera’Kyoho ’grapes as test material, the fluorescence indices of grape leaves were measured by FMS-2 fluorimetry to investigate the effects of drought on PSⅡ photochemical efficiency and light energy allocation of grape leaves. The results showed that the excess light energy (Ex) of leaves was significantly higher than that of the control on the first day of water control. The light absorbed by the leaves on the second day of water control applied to the proportion of antenna heat dissipation (D), non-photochemical quenching (NPQ) was significantly higher than that of the control, and the proportion of photosynthetic reaction (P) was significantly lower than that of the control. On the third day after watering, the antenna conversion efficiency (F’v / F’m), actual photochemical efficiency (ΦPSⅡ) (Β / α-1) of the two light systems was significantly higher than that of the control. The photochemical quenching coefficient (qP) of the leaves on the fourth day was significantly lower than that of the control. The maximum photochemical efficiency (Fv / Fm) was significantly lower than that of control after 4 days water control. Thus, under drought stress, the plant leaves first mitigate the damage of photosynthetic apparatus by the distribution of light energy, and then protect the photosynthetic apparatus by reducing the light energy absorption. The latter part of the water stress aggravates PSII reaction Center to reduce the degree of opening, photochemical reaction efficiency decreases, the final photoinhibition.