Preliminary study on leaf color development and photosynthetic characteristics of golden-leaf ginkgo | 榛舵插插瑰绌

[Objective] The aim of this study is to research leaf color development and photosynthetic characteristics of golden-leaf ginkgo. [Method] With one-year-old grafted seedlings of golden-leaf ginkgo as the materials, the changes of leaf color, chlorophyll content (Chl), carotenoid (x.c) content and rate of chlorophyll and carotenoid content, as well as photosynthetic characteristics under full sunlight and overshadowing were all investigated in this study. [Result] Sprouts of golden-leaf ginkgo were pale-yellow, and changed from orange to golden in April, to light yellow-green in May, to yellow-green from June to October, to yellow in November. The chlorophyll and carotenoid contents and the rates of chlorophyll and carotenoid contents of yellow-leaf were significantly lower than that of green-leaf, while the rate of Chla/x.c and Chlb/x.c was obviously lower than the corresponding pigment content of green-leaf. During the leaf color development, Chla, Chlb and x.c content as well as the rate of Chla/x.c and Chlb/x.c of yellow-leaf ginkgo all increased. The saturation light intensity of ginkgo leaf under natural light was higher than that under overshadowing. Maximum net photosynthetic rate, light compensation point and dark respiration rate of yellow leaf were all significantly higher than that of green leaf. Chla/x.c, Chlb/x.c and Chla+b/x.c of yellow-leaf ginkgo under overshadowing were higher than the corresponding pigment rate of leaf under natural light. [Conclusion] The best ornamental duration of golden-leaf ginkgo is April and May. The major reason for showing yellow leaf is that Chla/x.c and Chlb/x.c of yellow-leaf is obviously lower than that of green-leaf. During the leaf color development, the major reason for yellow-leaf turning to yellow-green is that the rate of Chla/x.c and Chlb/x.c increases. Chlb content of yellow-leaf under overshadowing is higher than that under natural light, which is an adaptive response to overshadowing. Chla/x.c, Chlb/x.c and Chla+b/x.c of yellow-leaf under overshadowing are relatively higher, which is one of the reasons why yellow-leaf under overshadowing becomes yellow-green or green.