连续剪梢对金叶女贞不同叶位呈色和光合特性的影响

Effects of continuous tip pruning on middle and lower leaf coloring and photosynthetic characteristics of Ligustrum vicaryi L.

为探究连续剪梢条件下金叶女贞(Ligustrum vicaryi L.)中、下部叶片呈色和光合生理特性的变化规律,以2年生的盆栽金叶女贞为材料,测定2011年5月、2011年7月和2011年9月连续剪梢处理下金叶女贞中、下部叶位叶片光合色素含量、光合速率(Pn)及叶绿素荧光参数的变化。结果显示:连续剪梢处理增加了金叶女贞叶片叶绿素含量,利于光合作用。连续剪梢处理增加了金叶女贞中部叶位叶片白天光能捕获能力、转换效率和电子传递活性,但连续剪梢处理导致午间中部叶位叶PSII反应中心的电子传递严重受阻,实际光化学效率下降,从而加剧了午间PSII反应中心的光抑制程度。此外,连续剪梢处理增加了金叶女贞叶片叶绿素/类胡萝卜素值,不利于叶片色彩的呈现。表明在栽培修剪管理中,为了充分发挥金叶女贞叶片的观赏价值,应适当保留上部金黄叶片。

To study the effect of tip pruning on coloring and photosynthesis of middle lower leaves in Ligustrum vicaryi L. , 2-year-old pot cultured Ligustrum vicaryi L. were used as materials to determine the changes of pigments con- tents, net photosynthetic rate （Pn） and chlorophyll fluorescence parameters under continuous pruning tips in May 2011, July 2011 and September 201 I. The results showed that continuous tip pruning improved the chlorophyll contents in middle and lower leaves of Ligustrum vicaryi L. ,which being good for photosynthesis. Continuous tip pruning overall increased the energy capture capability, conversion efficiency and electron transfer activity of middle leaves in daytime. However, PS II actual electron transfer at noon were blocked, leading to the decline of photochemical efficiency （Yield） and photoinhihition. Furthermore, continuous pruning added Chl/Car, which was unfavorable for leaf color presentation. It is appropriate to retain the upper golden leaves of L. vicaryi L. in gardening for its ornamental value.