不同砧木对黄果柑光合特性、光合作用关键酶及其基因表达的影响

Effects of different rootstocks on photosynthetic characteristics,activities and gene expression of key enzymes of photosynthesis in Huangguogan

为了从光合生理方面了解砧木对黄果柑的影响,以枳壳、红橘和香橙为砧木,黄果柑实生苗为对照,在果实成熟期测定其净光合速率(Pn)、蒸腾速率(Tr)、胞间CO_2浓度(Ci)、气孔导度(Gs)等日变化参数和光合响应曲线,以及核酮糖1,5-二磷酸羧化酶/加氧酶(Rubisco)含量、Rubisco活化酶(RCA)含量以及Rubisco基因(rbc S和rbc L)及其活化酶基因(rca)表达的影响。结果表明:不同砧木嫁接的黄果柑叶片净光合速率日变化曲线均呈双峰型,存在光合午休,3种嫁接树的净光合速率均大于实生苗;其蒸腾速率的日变化均呈单峰型,水分利用效率的日变化均为双峰型。此外,香橙嫁接的黄果柑叶片有较高的净光合速率、Rubisco含量和RCA含量及较强的rbc和rca基因表达。综合比较分析,香橙砧适宜作为黄果柑的砧木进行推广。

In order to understand the effects of rootstocks on photosynthetic physiology of Huangguogan,trifoliate orange,red tangerine and orange were used as rootstocks,Huangguogan seedling tree was set as the control,the daily variation of parameters and photosynthetic response curves of net photosynthetic rate（ Pn）,transpiration rate（ Tr）,intercellular CO_2concentration（ Ci） and stomatal conductance（ Gs）,contant of ribulose 1,5-biphosphate carboxylase/oxygenase（ Rubisco） and Rubisco activase,and the expression of rbc S,rbc L and rca genes were determined and compared in fruit mature period. The results showed that the net photosynthetic rate curve showed a double peak type with a photosynthetic noon break,net photosynthetic rate of three kinds of grafted trees were higher than the seedling trees; the diurnal variation of transpiration rate showed a single peak type,and the diurnal changes of water use efficiency were double peak type. In addition,the leaves with orange rootstock showed higher carboxylase activity of Rubisco and net photosynthetic rate and higher expression levels of rbc and rca genes than those others. Comprehen-sive comparative analysis showed that the orange rootstock was suitable as rootstock for Huangguogan.