Stem Photosynthesis of Twig and Its Contribution to New Organ Development in Cutting Seedlings of Salix Matsudana Koidz.

作   者：Junxiang Liu, Lin Gu, Yongchang Yu, Guansheng Ju , Zhenyuan Sun
期刊名称：Forests
影响因子：1.956
卷 期 号：9,207
页     码：
关键词：stem photosynthesis; organ development; cutting seedling; nonstructural carbohydrate;
论文摘要：
The objective of this study was to illustrate the photosynthetic characteristics of
current twigs of Salix matsudana Koidz., and clarify the effect of stem photosynthesis on the
new organ development in cutting seedlings. Excised twigs were taken as the experimental
samples. The response of the stem photosynthesis rate to increasing light intensity and the effective
photochemical efficiency of the cross section of the twig were determined. Then, twigs were used
as cuttings and exposed to 0, 20, and 100 mol m􀀀2 s􀀀1 light intensities, respectively, to achieve
distinctive stem photosynthetic rates. After 14 days of treatment, stem water and non-structural
carbohydrate (NSC) content, as well as the biomass and carbon isotopic composition, of new organs
in the cutting seedlings under different light treatments were examined. The results showed that the
gross photosynthetic rate significantly increased within 400 mol m􀀀2 s􀀀1 of light intensity, and the
maximum rate was approximately 1.27 mol m􀀀2 s􀀀1. The effective photochemical efficiency of the
PSII of the cortex was significantly higher than the inner tissues in the cross section of the twig. When
twig cuttings were exposed to different light intensities, stem water and starch content, as well as bud
and root biomass, were significantly higher in the cutting seedling subjected to 100 mol m􀀀2 s􀀀1
than the case treated in darkness; however, the bud d13C trend was the opposite. Stem photosynthesis
played a positive role in the maintenance of stem water and starch supply for the cutting seedlings,
and 13C depleted assimilates produced by stem photosynthesis contributed to bud biomass, revealing
that stem photosynthesis promotes organ development in cutting seedlings of Salix matsudana.