Effects of Leaf Types on Growth and Chlorophyll Fluorescence Characteristics in Pinus massoniana Seedlings

Objective: In this study, effects of leaf types on growth and chlorophyll fluorescence characteristicsin Pinus massoniana seedlings were studied in order to provide scientific basis for selection and cultivation. Method: One-year-old seedlings of P.massoniana have three different leaf types, such as primary needles, needles and intermediate type, at nursery stage. In this experiment, the growth traits, photosynthetic pigment contents and chlorophyll fluorescence parameters were investigated on one-year-old seedlings of P.massoniana. The chlorophyll fluorescence characteristics of primary and secondary leaves and their effects on seedling growth were studied. Result: The results showed thatthequality index (QI) at nursery stage, dry matter accumulationand growth traits one year after afforestation of the seedlings with needle swere significantly better than those with primary needles. The leaf length, volume and surface area of needles were significantly larger than the primary needles. Contents of chlorophyll a, chlorophyll b and total chlorophyll in primary needles were much higher than those in needles, while there was no significant difference in the content of carotenoid between the two types of needles. For chlorophyll fluorescence parameters, the Fm, Fv/Fm and Fv/Fo in primary needles were significant higher than thosein needles.There was no significant difference in Fo between the two leaf types.The Y(Ⅱ) and Fv'/Fm' of PSⅡreaction center, qP and NPQ of quenching parameter, Y(NPQ) and Y(NO) of energy dissipation and the photoresponse parameters, such as ETRmax, α, β and Ik in primary needles were significant higher than those in needles.It was indicated that the primary needles performed much better on the content of chlorophyll and light inhibition, with higher photosynthetic efficiency than needles, while the heat dissipation and non-photochemical quenching would increase under the intensivelight. However, due to larger leaf length, volume and surface area than primary needles, the seedlings with needles were able to obtain more light for photosynthesis and hence produce more dry matter. The quality indexat nursery stage and growth after afforestation of the seedlings with needle swere higher than those of the seedlings only with primary needles. Conclusion: The primary needles performed much better on the content of chlorophyll and light inhibition, with higher photosynthetic efficiency than needles, and the heat dissipation and non-photochemical quenching would increase under the intensive light in order to reduce the damage of excess light energy to photosynthesis system.The seedlings with needles had better seedling quality and growth characteristics. © 2019, Editorial Department of Scientia Silvae Sinicae. All right reserved.