Photosynthetic induction responses to variable light under field conditions three species grown in the gap and understory of Fagus crenata forest.

短句来源本研究对生长在山毛榉林隙和林下的毛毛榉（Fagus crenata）、水杨树（Daphniphyllum humile）和槭（Acer rufinerve）三种植物叶片进行了原位光合诱导响应研究，结果表明，在黑暗和100 μ mol光子m^<-2>s^<-1>的条件下，光子通量密度（PFD）突然增加到800和1500 μ mol光子m^<-2>s^<-1>。在100 μ mol光子背景PFD m^<-2>s^<-1>，以及A_<100>/A_<max> （A_<max>：最大同化速率）下，毛茛在林隙和林下均表现出最大的同化速率（A_<100>）和气孔导度（g^<s100>）。实现完全感应所需的时间取决于背景PPD和高pfd。100 μ mol光子m_<-2> s_<-1>的地面PFD诱导周期比黑暗条件下短2-4倍。对于未知层中的三个物种，当光从黑暗增加到800 μ mol光子时，完全感应所需的时间是1500 μ mol光子（m_<-2>s_<-1>）的2-3倍。林下槭的初始气孔导度（g_< 50 >）高于林下，诱导期较林下短。在两种生境中，毛茛的g_< 50 >和诱导值趋于相似。腐殖质水蚤在林下的g_< 50 bb_0，诱导期较林隙长。这些结果表明，初始气孔导度与光合诱导反应密切相关。植物在辐照度突然增加之前所经历的光照条件和增加的程度影响光合诱导反应。

Photosynthetic induction responses to variable light were examined in situ for leaves of three species, Fagus crenata, Daphniphyllum humile, and Acer rufinerve, grown in the gap and understory of a Fagus crenata (Japanese beech) forest, with abrupt increases in photon flux density (PFD) to 800 and 1500, mu mol photons m^<-2> s^<-1> from either darkness or 100 mu moM photons m^<-2>s^<-1>. Fagus crenata exhibited the greatest assimilation rate (A_<100>), stomatal conductance (g^<s100>) at the back ground PFD of 100 mu mol photons m^<-2>s^<-1>, and A_<100>/A_<max> (A_<max> : maximum assimilation rate) both in the gap and understory. Time required to achieve full induction depend on both background PPD s and high PFDs. induction period at the ground PFD of 100 mumol photons m_<-2> s_<-1> was 2-4-fold shorter than in darkness. For the three species in the uncierstory, time required to full induction was 2-3-fold Longer as the light was increased from darkness to 800 than to 1500 mumol photons m_<-2>s_<-1>. Acer rufinerve in the understory showed greater initial stomatal conductance (g_<s0>) and shorter induction period than in the gap. Fagus crenata tended to have similar g_<s0> and induction in both habitats. Daphniphyllum humi(e demonstrated lower g_<s0> and a longer induction period in the understory than in the gap. These findings indicate that initial stomatal conductance is closely correlate to the photosynthetic induction response. Light conditions plants experienced before a sudden increase in irradiance and the degree of the increase affected the photosynthetic induction response.