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干旱和光照不足是干扰玉米光合作用 ,进而影响玉米高产的重要限制因素。为了了解玉米叶绿素非光化学荧光猝灭 (q N)对干旱和遮光逆境的反应 ,我们研究了 q N的主要叶绿素荧光参数。结果表明 :(1)干旱和遮光处理显著增加了最大值时的 q Nmax和稳定态时的 q Ns,降低了 PS 电子传递的光量子产量 (ΦPS )。 (2 ) q Ns与 q Nmax的比值与逆境的严重程度相符合 ,它在各处理间的变化趋势与植株干物重减少的百分率 (RDDMW)一致。 (3)干旱和遮光在一定程度上影响了 q N到达最大值或稳定态的时间和速率。其中 q N到达稳定态的速率 (Rq Ns)是一个非常有意义的指标 ,它在严重的干旱 (DD)和遮光 (SS)处理下最低 ,在较轻的干旱 (DR)和遮光 (SR)处理下较低 ,在对照中最高。 Rq Ns在各处理间的变化趋势与植株干物重基本一致。 (4)遮光处理主要增加与能量耗散有关的 q N的快组分 (q E) ,而干旱处理主要增加与状态转换有关的 q N的中组分 (q T)。
Droughts and inadequate lighting are important constraints that interfere with maize photosynthesis and thus maize yield. In order to understand the response of maize chlorophyll non-photochemical fluorescence quenching (q N) to drought and shading stress, we studied the main chlorophyll fluorescence parameters of q N. The results showed that: (1) The q Nmax at the maximum and the q Ns at the steady state were significantly increased under drought and shading treatments, and the photon yield (ΦPS) of PS electron transfer was reduced. (2) The ratio of q Ns to q Nmax agrees well with the severity of adversity, and its trend of change among the treatments is consistent with the percentage of dry matter weight loss (RDDMW). (3) Drought and shading to a certain extent affect the time and rate at which q N reaches the maximum or steady state. Among them, the rate of q N reaching steady state (Rq Ns) is a very significant index, which is the lowest under severe drought (DD) and shading (SS) treatment. In light drought (DR) and shading (SR) Lower treatment, the highest in the control. The trend of Rq Ns in all treatments was basically the same as that of plant dry weight. (4) The shading treatment mainly increases the fast component (q E) of q N related to energy dissipation, whereas the drought treatment mainly increases the medium component (q T) of q N related to state transition.