不同光周期对岭南山竹子生存率、叶片结构及光合特性的影响OA

Garcinia oblongifolia is a priority tree species for the restoration and reconstruction of planted forests surrounding the habitat of the Hainan gibbon(Hylobates hainanus),and light conditions are considered one of the key environmental fac-tors affecting its survival.In this study,different photoperiod treatments(natural,extended,and shortened)were used to in-vestigate their effects on the survival,leaf structure,and photosynthetic physiological characteristics of G.oblongifolia to provide a theoretical basis for determining the optimal photoperiod for its growth and development.The results showed that(1)the survival rate of G.oblongifolia under the shortened photoperiod was significantly lower than that under the natural and extended photoperiods.(2)The contents of chlorophyll a,chlorophyll b,and total chlorophyll in G.oblongifolia leaves under the natural and extended photoperiods were significantly lower than those under the shortened photoperiod,while the chloro-phyll a/b ratio was significantly higher.(3)Under the natural photoperiod,the leaf lightness(L*),yellowness(b*),and chroma(C*)values of G.oblongifolia leaves showed an increasing trend over time,whereas the redness-greenness(a*)value showed a decreasing trend.The temporal changes in these color parameters under the extended and shortened photoperiods were rela-tively complex.(4)Stomatal width,stomatal area,stomatal density,stomatal aperture,and stomatal aperture ratio of G.oblongifolia leaves under the extended photoperiod were significantly higher than those under the natural and shortened pho-toperiods,whereas stomatal length was significantly lower than that under the shortened photoperiod.(5)Palisade tissue thickness,palisade-to-sponge mesophyll ratio,leaf tissue compactness,stomatal conductance,transpiration rate,and intercel-lular CO2 concentration of G.oblongifolia leaves under the shortened photoperiod were significantly lower than those under the natural and extended photoperiods.The net photosynthetic rate under both the extended and shortened photoperiods was significantly lower than that under the natural photoperiod,with no significant difference between the extended and shortened photoperiods.These results indicate that the shortened photoperiod mainly affects the photosynthetic characteristics of G.oblongifolia,reduces its net photosynthetic rate,and consequently decreases its survival rate.Therefore,photoperiod is one of the main factors affecting plant survival in the restoration and reconstruction of planted forests.This study is of great signifi-cance for the restoration and reconstruction of planted forests surrounding the habitat of the Hainan gibbon.