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为了解生长旺盛期的白魔芋(Amorphophallus albus)对不同光强环境的适应机制,通过模拟白魔芋在农业生产中常见的3种生长光环境(高光、中光、低光),研究叶片气体交换和叶绿素a荧光参数的变化.结果显示:随着生长环境光强的减小,白魔芋的暗呼吸速率和表观量子产额显著增大(P<0.05),且在低光下最大净光合速率(A_(max))、水分利用效率和羧化效率具有最大值,光补偿点和CO_2补偿点在高光条件具有最大值;高光生长环境下白魔芋对光合诱导反应更迅速,且随着初始气孔导度(G_(s-initial))的增大,达到最大净光合速率30%、50%和90%所需的时间逐渐降低.低光生长环境下白魔芋的光系统II(PSⅡ)光下最大光化学效率(F_v′/F_m′)、实际光化学效率(ΔF/F_m′)、非光化学淬灭(NPQ)和电子传递速率(ETR)具有最大值;高光生长环境下白魔芋将更多光能分配到非光化学途径(Φ_(NPQ)),而中、低光生长环境下光化学途径(Φ_(PSⅡ))比例较高.综上表明,处于生长旺盛期的白魔芋在中、低光生长环境下有着较高的光合效率,并通过增加热耗散增强光保护能力;高光生长环境下白魔芋具有较快的光合诱导速率,同时通过增强PSⅡ抑制状态的转换能力等策略来适应高光,从而避免光合机构不可逆的损伤.(图8表2参45)
In order to understand the adaptation mechanism of Amorphophallus albus to different light intensity environments during growing season, three kinds of growth light conditions (high light, medium light, low light) commonly used in agricultural production were simulated to study leaf gas exchange And chlorophyll a fluorescence parameters were studied.The results showed that the dark respiration rate and apparent quantum yield of white konjac were significantly increased with the decrease of light intensity in the growth environment (P <0.05), and the maximum net photosynthesis (A max), water use efficiency and carboxylation efficiency had the maximum values, and the light compensation points and CO 2 compensation points had the maximum values under high light conditions. The white konjac photosynthetic induction reaction was more rapid under high light growth conditions. With the initial Stomatal conductance (G-s-initial), the time required to achieve the maximum net photosynthetic rate of 30%, 50% and 90% decreased gradually.The photosystem II (PSⅡ) light The maximum photochemical efficiency (F_v ’/ F_m’), the actual photochemical efficiency (ΔF / F_m ’), the non-photochemical quenching (NPQ) and the electron transfer rate (ETR) have the maximum value under high light growth conditions; Can be assigned to non-photochemical route (Φ_ (NPQ)), while in low light The photosynthetic pathway (Φ_ (PSⅡ)) had a higher proportion of photosynthetic pathway (Φ_ (PSⅡ)) in a long time.Conclusion: The white konjak at high vigorous growth has higher photosynthetic efficiency under medium- and low-light growth environment and enhanced light protection by increasing heat dissipation Ability; the high-light growth environment of white konjac has a faster rate of photosynthetic induction, at the same time by enhancing the ability of PS Ⅱ to inhibit the state of the conversion ability to adapt to high light, so as to avoid irreversible damage to photosynthetic machinery (Figure 2, Table 2, 45)