间作和净作条件下喜阴植物谢君魔芋的光合作用及光合诱导特征研究

Photosynthesis and Photosynthetic Induction of Shade-tolerant Species Amorphophallus xiei under Intercropping and Monoculture Planting Patterns

摘要:

为了解种植模式对谢君魔芋（Amorphophallus xiei）光合作用的影响，研究了间作和净作模式下谢君魔芋的光合作用和光合诱导特征。结果表明，间作模式下的谢君魔芋净光合速率（P_n）比净作模式的高18.97%，最大气孔导度（g_s-max）比净作模式的小22.4%，且间作模式下谢君魔芋有较高的表观量子产额（AQY）、光饱和点（LSP）、羧化效率（CE）、叶绿素含量以及较小的暗呼吸速率（R_d）、光补偿点（LCP）、CO₂补偿点（Г^*）。高光照诱导后，间作模式下的光合诱导状态（IS）大于净作模式，且在间作模式下光合诱导过程中达到最大光合速率（P_max）和最大气孔导度（g_s-max）的30%、50%所需时间较短；同时，光合诱导过程中达到P_max和g_s-max的30%、50%和90%的时间（t_{30% P}、t_{50% P}、t_{90% P}和t_{30% gs}、t_{50% gs}、_{t90% gs}）与gs-initial呈负相关关系。因此，玉米-魔芋间作下，谢君魔芋通过增大AQY和LSP、减小R_d和LCP等来提高光的利用能力及维持碳平衡；同时通过快速的光合诱导，提高对光斑的利用能力从而增加碳获得。

Abstract:

In order to understand the effect of planting pattern on photosynthesis of Amorphophallus xiei, the photosynthesis and photosynthetic induction were studied under intercropping and monoculture planting patterns. The results showed that the net photosynthetic rate (P_n) of A. xiei under intercropping was 18.97% higher than that under monoculture and the maximum stomatal conductance (g_s-max) was 22.4% lower than that under monoculture. There were high apparent quantum yield (AQY), light saturation point (LSP), carboxylation efficiency (CE) and chlorophyll content as well as lower dark respiration rate (R_d), light compensation point (LCP) and CO₂ compensation point (Г^*) in A. xiei under intercropping. After inducted by high illumination, the photosynthetic induction state (IS) under intercropping was higher than that under monoculture. During photosynthetic induction, the time required to reach 30% and 50% of P_max were short under intercropping. There were negative relation between initial stomatal conductance (gs-initial) and the time required to reach 30%, 50% and 90% of P_max and g_s-max. Therefore, it was suggested that light utilization capicity and carbon balance of A. xiei would enhance by rising AQY and LSP and decreasing R_d and LCP under intercropping with Zea mays, and at the same time, the capacity of facula utilization increased by rapid photosynthetic induction, and thus, increasing carbon gain.