修剪对蜡梅光合作用和叶片解剖特征的影响

以6年生蜡梅为试材,研究修剪对蜡梅光合作用和叶片解剖特征的影响。在蜡梅生长旺盛期,测定蜡梅光合参数,观察叶片解剖结构。结果表明:修剪组蜡梅叶片的净光合速率、气孔导度和蒸腾速率日均值显著高于对照,表观叶肉导度极显著高于对照,胞间二氧化碳浓度显著低于对照;修剪组叶片的叶绿素a和叶绿素总量均显著高于对照,叶绿素a与叶绿素b的比值和气孔宽度极显著大于对照,气孔长、气孔开度宽、气孔密度均显著大于对照;修剪组叶片厚度和栅栏组织厚度均显著大于对照,栅海比极显著大于对照;相关分析结果表明,Pn与Tr、Gs、ALMC、PAR、Ta、叶绿素a与叶绿素b的比值、比叶重、气孔长、气孔宽、气孔开度宽均呈显著正相关;因此,修剪可改变蜡梅叶片形态特征和提高蜡梅的光合效率,有利于蜡梅生长。

Effects of pruning on photosynthesis and leaf anatomical characteristics ofChimonanthus praecox

TheChimonanthus praecox of six years old was used as material to study the effects of pruning on photosynthesis and leaf anatomical structure. The photosynthetic parameters were measured and anatomic characteristics was observed in vigorous growth period of the leaf. The results showed that the pruning significantly increased the average of diurnal variation of net photosynthetic rate (Pn), stomata conductance (Gs) , transpiration rate (Tr) ofChimonanthus praecox leaf , the apparent mesophyll conductance (ALMC), the chlorophyll a , total chlorophyll content , the ratio of chlorophyll a to chlorophyll b , width of stoma , the length of stoma, width of stomata aperture, stomata density , the thickness of leaf , palisade tissue , the thickness rate of palisade and sponge tissue , however, significantly decreased the intercellular CO2concentrations(Ci). Correlation analysis showed that the net photosynthetic rate was significantly positively correlated withTr,Gs, ALMC,PAR,Ta, the ratio of chlorophyll a to chlorophyll b, the specific leaf weight, the width of stoma, the length of stoma and width of stomata aperture. In conclusion, the pruning could change the leaf morphological characteristics and anatomical structure characteristics and photosynthetic efficiency of the leaves, which were beneficial to the growth ofChimonanthus praecox.