降尘对阿克苏地区主栽果树叶片光合特性及叶绿素荧光特性的影响

为探讨长期叶面降尘对阿克苏地区主栽果树叶片光合性能的影响，于6—8月以苹果(Malus pumila)、核桃(Juglans regia)、枣(Ziziphus jujube)3种果树为试验材料，分别选择自然状态下接受降尘影响的样树5株为降尘处理，以每7 d用清水冲洗一次叶片的样树5株为对照处理，对比分析叶片滞尘量、光合参数、荧光参数和叶绿素含量的变化。结果表明：3种果树叶片滞尘能力为苹果>枣>核桃。3种果树降尘处理植株的叶片叶绿素含量(Chl)、净光合速率(P_n)、气孔导度(G_s)和蒸腾速率(T_r)均显著(P<0.05)低于对照植株，胞间CO₂浓度(C_i)则显著(P<0.05)高于对照植株，并且降尘处理时间越久，对果树叶片叶绿素含量及光合参数的影响越大。此外，3种果树降尘处理植株最大光化学效率(F_v/F_m)、光化学淬灭系数(qP)显著低于对照植株，最小荧光(F_o)、非光化学淬灭系数(NP...

Effects of dustfall on photosynthetic characteristics and chlorophyll fluorescence characteristics of major fruit trees in Aksu Region,China

In order to explore the effect of long-term foliar dusts on photosynthetic performance of leaves in main fruit trees of Aksu area, Malus pumila, Juglans regia and Ziziphus jujube were used as experimental materials from June to August, five sample trees affected by dustfall in natural state were selected as dustfall treatment, and five sample trees whose leaves were washed with clear water every seven days were used as control treatments, respectively. The changes in dust absorption amount, photosynthetic parameters, fluorescence parameters and chlorophyll content in leaves were compared and analyzed. The results showed that the dust absorption ability of leaves in three fruit trees was as follows: Malus pumila>Ziziphus jujube>Juglans regia. The chlorophyll content (Chl), net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r) in three kinds of fruit trees treated with dustfall were significantly (P<0.05) lower than those in the control plants, while the intercellular CO₂ concentration (C_i) was significantly (P<0.05) higher than that in the control plants. The longer the dust absorption time was, the greater the influence on Chl and photosynthetic parameters of fruit trees was. In addition, the maximal photochemical efficiency (F_v/F_m) and photochemical quenching coefficient (qP) in three kinds of fruit trees treated with dustfall were significantly (P<0.05) lower than those in the control plants, while the minimal initial fluorescence (F_o) and non-photochemical quenching coefficient (NPQ) were significantly (P<0.05) higher than those in the control plants. Correlation analysis showed that there was a significant negative correlation between dust absorption and P_n, Chl and F_v/F_m in leaves of three kinds of fruit trees at P<0.05 and P<0.01 level, respectively. The main factor limiting P_n in leaves of three kinds of fruit trees under dustfall treatment was non-stomatal factor. Dustfall caused some damage or reversible inactivation of PSⅡ reaction center in fruit tree leaves, which reduced the original light energy conversion efficiency of fruit tree leaves, thus affecting the normal photosynthesis. The research results can provide a scientific theoretical basis for the cultivation and management of main fruit trees in Aksu area.