美洲黑杨不同生长势子代及其亲本叶片淀粉和蔗糖代谢特征差异分析

This study aimed to investigate the differences in key indicators of starch and sucrose metabolism in the leaves of F1 hybrids with different growth potentials and their parents Populus deltoides at different forest ages during critical growth periods,analyze the role of starch and sucrose metabolism in the formation and maintenance of growth heterosis of P.deltoides,and clarify the sugar metabolism characteristics of hybrids with superior growth-trait in Populus.Utilizing the space-for-time substitution method,the high-growth potential hybrids(H1,H2,H3)and low-growth potential hybrids(L3,L4),along with their male(MP)and female(FP)parents of P.deltoides in 1-and 3-year-old during the peak growth season(June,July,August,September),were selected as the research materials.The content of starch and sucrose in the leaves at different time points,as well as the activities of ADP glucan pyrophosphate synthase(AGPase),sucrose phosphate synthase(SPS),β-amylase(BAM),and sucrose synthase(decomposition direction,SS-I),were measured using micro-methods.The study compared the differences of various indicators among hybrids and parents,conducted correlation,regression equations,and path analysis,to elucidate the regulatory patterns of key indicators in starch and sucrose metabolism that contributed to formation of different growth potential.During the peak growth season,high-growth potential hybrids in 1-and 3-year-old exhibited significant high-parent heterosis(HPH)for tree height,ground diameter(GD),and diameter at breast height(DBH),and were significantly higher than those of low-growth potential hybrids(p＜0.05);In August and September,high-growth potential hybrids demonstrated notable mid-parent(MPH)or high-parent heterosis in starch and sucrose breakdown capacity at night and synthesis capacity during the day.Specifically,the MPH for nighttime starch consumption,AGPase activity,and BAM activity were 1.24％-12.20％,0.42％-18.40％,and 0.54％-5.20％,respectively,and the HPH for nighttime sucrose consumption and SPS activity were 0.29％-26.05％and 0.61％-16.03％,respectively,while these indicators showed opposite trends in low-growth potential hybrids.However,SS-I activity in low-growth potential hybrids showed high-parent heterosis(HPH:0.87％-11.81％)and was higher than in those with high-growth potential hybrids.The net monthly growth in tree height and DBH(GD)of P.deltoides during the peak growing season was significantly positively correlated with AGPase activity,SPS activity,and nighttime starch consumption.Additionally,the direct positive effects of SPS,AGPase,and BAM enzyme activities on the net monthly growth in tree height and DBH(GD)of P.deltoides during the peak growth season were significant.High-growth potential hybrids of P.deltoides exhibited stable growth heterosis,and they showed significant MPH and HPH in the nighttime decomposition capabilities and daytime synthesis abilities of starch and sucrose.Enhanced activities of SPS,AGPase,and BAM enzymes could effectively promote and sustain the formation of high-growth potential in P.deltoides.The results provide useful references for elucidating the mechanism by which starch and sucrose metabolism contribute to the formation of growth heterosis in hybrids of trees and breeding for super high yield.