不同黄化程度对杂柑幼苗生长及光合作用的影响

摘要

为了研究不同黄化程度对柑橘幼苗生长及光合作用的影响,以黄果柑、不知火幼苗为材料,分析黄化苗、花叶苗和绿叶苗的生长量、叶绿素含量、光合及叶绿素荧光参数的变化.结果表明,叶片黄化抑制了幼苗的正常生长,黄化苗的生长量显著低于绿叶苗;黄化苗叶片中游离脯氨酸(Pro)、丙二醛(MDA)、可溶性糖(SS)和可溶性蛋白质(SP)含量均显著增加;叶片黄化显著降低了叶片叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)含量和光合作用气体交换参数(气孔导度、胞间CO2浓度、蒸腾速率),改变了叶绿素的组成比例.黄化苗的PSⅡ最大光化学效率(Fv/Fm)、光化学猝灭系数(qP)和非光化学猝灭系数(NPQ)显著低于绿叶苗,导致净光合速率(Pn)显著降低,但花叶苗Fv/Fm下降程度较小.研究表明,叶片黄化抑制了黄果柑、不知火幼苗的正常生长,降低了光合能力.%In order to study the effect of different etiolation degrees on Citrus seedling growth and photosynthesis, Citrus cultivars Huangguogan and Shiranuhi seedlings were used as the materials, to analyze the changes of seedling biomass, chlorophyll content, photosynthetic parameters and chlorophyll fluorescence characteristics of etiolated, multicoloured and green seedlings. The results showed that the normal growth of Citrus cultivars Huangguogan and Shiranuhi seedlings was inhibited by etiolation, and the growth of etiolated seedlings was significantly lower than that of green seedlings. The contents of free proline ( Pro) , malondialdehyde ( MDA) , soluble sugar ( SS) and soluble protein ( SP) were significantly increased in the leaves of etiolated seedlings. Seedling etiolation could significantly reduce the content of chlorophyll a, chlorophyll b, carotenoid and photosynthetic gas exchange parameters ( stomatal conductance, intercellular CO2 concentration, transpiration rate), and change the composition ratio of the chloro-phyll. Maximal photochemical efficiency ( Fv/Fm ) , photochemical quenching ( qP ) , and non-photochemical quenching ( NPQ) of etiolated seedlings were significantly lower than those of green seedlings, but the Fv/Fm of mul-ticoloured seedlings was decreased slightly. This study indicated that seedling etiolation inhibited the normal growth and photosynthetic capacity of Citrus seedlings.