作 者 ：赵明;石井龙一;丁在松; 姜雯;陈丽
期 刊 ：作物学报 2005年 31卷 12期 页码：1544-1551
关键词：玉米(ZeamaysL.)；小麦(TriticumaestivumL.)；光合作用；非光化学猝灭；
Keywords:Maize(ZeamaysL.), Wheat(TriticumaestivumL.), Photosynthesis, Non-photochemicalquenchingofchlorophyllfluorescence,
摘 要 ：为了比较玉米(Zea mays L.)（C4）与小麦 (Triticum aestivum L.)（C3）黑暗向光照变化过程中的光诱导适应性反应，对非光化学猝灭（Non-photochemical quenching, qN）的动态变化特征进行了观察和分析。结果表明，在15 min至24 h的不同暗适应处理中，根据qN的光适应的动态变化可分为F型（快速稳定型）、M型（中速稳定型）和S型（慢速稳定型）3种。在暗适应后的光诱导期间，小麦qN主要表现出M和F型，玉米则表现出S和M型。通过对主要的荧光参数分析，小麦与玉米的Fv/Fm,qp和ΦpsII差异较小，而且qN稳定值有一定的差异，但TqNmex(qN达到最大值的时间）和TqN（qN达到稳定值的时间）玉米明显高于小麦，差异极明显。进一步分析经黑暗处理后光诱导的光合速率和气孔导度的动态变化，两作物虽然在增加的速率和稳定后的绝对值有差异，但达到稳定的时间无明显的不同。通过塑料膜包封叶片的方法阴止CO2同化，而qN变化特征也基本不改变。这意味着短时间的C代谢不明显影响qN对光诱导的反应。对光系统I反应中心P703的典型氧化还原方式的测定和电子库容能力的分析也表明它们不是造成qN动态变化的主要原因。然而，对qNmex成分的分析证明高能态猝灭（high-energy state quenching,qE）、转化猝灭（transition quenching,qT)和光抑制猝灭（photoinhibitory quenching,q1)分别为55.6%、18.5%和25.9%，说明qE是导致玉米qN在暗处理后的光诱导表现出TqNmex高、TqN长的主要原因。这意味着玉米（C4）在暗一光的变化中维持较高的qE，保持较高的类囊体质子梯度，有益于启动NADPH和ATP的形成。
Abstract:In order to compare the difference between maize (Zea mays L.) and wheat (Triticum aestivum L.) in response to adaptation from dark to light, the dynamics of non-photochemical quenching (qN) were observed and analyzed during photosynthetic induction. The results showed that the dynamics of qN could be classified into three types, which were F-form, M-form and S-form.During the dark adaptation from 15 minutes to 24 hours, wheat had F-form and M-form,while M-from and S-form were showed in maize. There was no marked difference between maize and wheat in Fv/Fm,qp and ΦpsII,while apparent difference existed in qN, and the time of reaching the maximum and steady-state of qN(expressed as TqNmtx and TqN, respectively),which were new parameters defined here, was markedly higher in maize leaves than in wheat leaves when tllumination occurred after dark adaptation. However, there was no apparent difference between maize and wheat in the time needed to reach the steady-state of photosynthetic rate(Pm) and stomatal conductance(Gs) under 1600 μmol·m-2·s-1 light intensity after dark adaptation. Meanwhile, the limitation of CO2 supplied to leaves with plastic film sealing up the leaves in a short period(less than 30 min) had a minimal effect on the dynamics of qN, which implied that the different dynamics did not result from the start of CO2 assimilation or stomatal regulstion. The messurement of the typical pattern for oxidation-reduction of P700 and the estimate of the functional pool size of intersystem electrons per reaction center supported our belief that the redox state of P700 in PSI and the pool size of the intersystem were not the main factors that led to great differences in dynamics of qN between maise and wheat. However, the analsis of the qN component showed that high-energy state quenching(qE), state transitional quenching(qT) and photoinhibitory quenching (q1) were 55.6%, 18.5%, and 25.9% of qN when reaching qNmex, respectively, which meant it might be qE that resulted in the different dynsmics of qN between maize and wheat. The results suggested that maize(C4) might have a higher qE to maintain the proton gradient of thylakoid than wheat (C3) for adapting to the transition from dark to light and to initate the use of NADPH and ATP by carbon fixation during photosynthetic induction.
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