不同遮阴处理对香草兰光合作用及花芽分化的影响

为探讨适宜香草兰生长发育的遮阴度,试验设50%、75%和90%这3种不同遮阴度的遮阴网处理,测定各处理条件下植株叶片的叶绿素相对含量和叶绿素荧光等光合参数,并跟踪统计各处理条件下的花芽分化率。结果表明:较低遮阴度不利于香草兰叶绿素形成;在一定范围内,表观量子效率(AQY)、实际光化学效率(ФPSⅡ)和天线转化效率(Fv′/Fm′)随遮阴度增加而增加;净光合速率(Pn)、气孔导度(Gs)、光饱和点(LSP)、暗呼吸速率(Rd)、PSII的潜在活性(Fv/Fo)、最大光化学效率(Fv/Fm)、表观光合电子传递速率(ETR)和光化学淬灭系数(qP)都随遮阴度增加呈先增加后降低的趋势;75%遮阴度下花芽分化率最高,达到54.98%。可见,香草兰适宜在遮阴度为75%的栽培条件下生长,生产中可参考应用。

Effects of Shading on Photosynthesis and Flower Bud Differentiation of Vanilla Plants

Field experiments were conducted on cultivation with varied shading materials over the plants to examine their effects on the photosynthesis and flower bud differentiation of vanilla.The shading materials provided 50％,75％,and 90％ shades.Three months after the treatments,the relative chlorophyll content,photosynthetic physiology and chlorophyll fluorescence of the plants were determined.In the following April,ratios of the flower bud formation were recorded.The results showed that the low shading was unfavorable for the chlorophyll formation on the plants.Within a certain range of the shading,the apparent quantum yield (AQY),effective quantum yield of photosystemⅡ (ΦPSⅡ) and efficiency of excitation captured by open PSII center (Fv'/Fm') increased with increasing shading.On the other hand,the net photosynthetic rate (Pn),stomatal conductance (Gs),light saturation point (LSP),dark respiration rate (Rd),potential photochemical efficiency (Fv/Fo),maximum photochemical efficiency (Fv/Fm),electron transport rat (ETR) and photochemical quenching coefficient (qP) increased initially and then decreased with increasing shading.The rate of flower bud formation was up to 54.98 ％ with the 75 ％ shading.Thus,it appeared that 75 ％ shading could be conducive to the vanilla growth,and applicable for its cultivation.