不同温度下喷施油菜素内酯对香椿幼苗的影响

Effects of spraying Brassinolide on growth and photosynthesis of seedlings of Toona sinensis in different temperatures

为了探究外源油菜素内酯(BR)对不同温度(8、28、38℃)下香椿幼苗生长的调节作用,以盆栽5月龄香椿幼苗为试材,以喷施清水为对照,研究外源油菜素内酯对不同温度下香椿幼苗生物量、叶绿素含量、光合特性、叶绿素荧光特性的影响。结果表明;外源BR处理可提高不同温度下香椿幼苗叶绿素的含量,显著提高香椿幼苗生物量和干物质积累量,使香椿幼苗叶片组织加厚,叶片相对含水率(RWC)提升,并且提高了香椿幼苗的净光合速率(P_n)、气孔导度(Gs)、最大光化学效率(F_v/F_m)、实际光化学效率(ΦPSⅡ)和光化学猝灭系数(qP),降低了胞间CO_2浓度(C_i)、蒸腾速率(T_r)、初始荧光(F_o)、非光化学猝灭系数(qN)。综上所述:喷施油菜素内酯可以促进适温下(28℃)香椿幼苗植株的生长,提高香椿幼苗在温度胁迫下的缓解作用和适应能力。

To investigate effects of spraying Brassinolide on the biomass,chlorophyll content,photosynthetic characteristics and chlorophyll fluorescence of seedlings of Toona sinensis in different Temperatures(8℃,28℃,38℃),5-month-old Toona sinensis seedlings were taken as the experimental material and the seedlings were sprayed with distilled water as the control.The results revealed that BR application increased the chlorophyll contents in different temperatures,significantly raised the seeding biomass and dry matter accumulation,thickened the leaf tissue and enhanced leaf relative water content of seedlings of Toona sinensis.With the BR treatments,the net photosynthetic rate,stomatal conductance,maximum photochemical efficiency,actual photochemical efficiency and photochemical quenching coefficient were increased.The rate of intercellular CO2concentration,transpiration rate,initial fluorescence and non-photochemical quenching coefficient were decreased.To sum up,the spraying Brassinolide treatments can promote the growth of seedlings of Toona sinensis in suitable temperature(28℃)and increase the mitigation and adaptation of seedlings of Toona sinensis to different temperature stress.