施肥对毛竹林幼竹生长期光合特性的影响

为了揭示施肥对毛竹光合能力的影响规律,研究了不同施肥模式下4年生毛竹在幼竹生长期(5月)的光合特性。结果表明:(1)5月施肥、8月施肥、不施肥3种处理下毛竹的净光合速率(Pn)、蒸腾速率(Tr)日变化均为"单峰"曲线,在13:00左右达到峰值。5月施肥Pn、Tr日平均值分别为4.14μmol/(m2.s)、1.12 mmol/(m2.s),均高于8月施肥和不施肥处理;(2)5月施肥毛竹的光饱和点(LSP)、最大净光合速率(Pnmax)、表光量子效率(AQY)、CO2饱和点(CSP)、羧化效率(CE)分别为:1512μmol/(m2.s)、9.45μmol/(m2.s)、0.0226 mmol/mol、1725μmol/mol、0.0265,均高于8月施肥和不施肥处理,而光补偿点和CO2补偿点低于其他处理。结果显示,换叶后的幼叶期(5月)施肥更有利于提高和维持毛竹的光合能力。

Effects of Fertilization on Photosynthetic Characteristics of Young Phyllostachys pubescens in Growing Period

This paper studied the effects of three different fertilization modes on the photosynthetic characteristics of 4-year-old Phyllostachys pubescens in the growing period(in May).The results showed that:(1) The diurnal variation in net photosynthetic rate(Pn) and transpiration rate(Tr) of Phyllostachys pubescens in three fertilization treatments all revealed the single-peak curve,and the peak occurred at about 13:00.The daily mean Pn and Tr value of Phyllostachys pubescens in the treatment of fertilization in May were 4.14 μmol/(m2·s) and 1.12 mmol/(m2·s) respectively,being higher than those in the treatment of fertilization in August and CK(no fertilization);(2) The light saturation point(LSP),maximum net photosynthetic rate(Pmax),apparent quantum yield(AQY),CO2 saturation point(CSP) and CE of Phyllostachys pubescens fertilized in May were 1512 μmol/(m2·s),9.45 μmol/(m2·s),0.0226 mmol/mol,1725 μmol/mol and 0.0265 respectively,being higher than those in the treatment of fertilization in August and CK.While the light compensation point and CO2 compensation point of Phyllostachys pubescens fertilized in May were lower than those in other treatments.Therefore fertilization in May was propitious to the enhancement and keeping of the photosynthetic ability in Phyllostachys pubescens.