Studies On Methods Of Breaking Dormancy And Germination Physiology Of Cyclocarya Paliurus (Batal.)Iljinskaja

Grown for its fine timber and as a medical plant, Cyclocarya paliurus(family Juglandaceae) is native to China and is the sole species in its genus. However, the seeds remain deeply dormant for two years in their natural environment. We tested different pretreatment of chemical scarification and exogenous application of gibberellic acid (GA3) for efficacy in breaking dormancy and speeding germination. Based on the same other treatments, the germination rate increased with sulphuric acid treatment time for eight hours, nine and ten hours. The germination rate for ten hours enhanced 4.9% and 8.4% than that of eight and nine hours. With the enhancement of GA3 concentration, the germination rate increased. In d0 media, the mean germination rate of exogenous GA3 treatment increased 10.7%　at　the　60th　day　and　17.7%　at　the　120th　day　than　the　control. In the stratification media moistened sands with 400 ppm GA3, the germination rate at 100th day exceed 90%., which was better than that in the media moistened sands with water. This was because that GA3 prolong the effect time. In practice, an appropriate treatment technique may be found out based on different objective and time. And during the natural stratification, the content of stored substance and endogenous hormones, some enzyme activity were investigated to find out the germination physiology of Cyclocarya paliurus seeds. The results are as follows. During seeds stratification under nature temperatures, the total activity of the lipase, amylase and endopeptidase increased, this change was concurrent to degradability of fat, amylum and protein. They prepared substance and energy for germination of seeds. The total activity of the POD and G6PDH increased, the action of PPP promoted in sugar-metabolize method. This indicated that the seeds of Cyclocarya paliurus was relieving dormancy and prepared for germination. The content of abscisic acid (ABA) in the Cyclocarya paliurus seeds reduced gradually, but the contents of gibberellic acid (GA),indole-3-acetic acid (IAA) and cytokinin (CTK) increased at the same time, and the ratios of gibberellic acid (GA)/ abscisic acid (ABA), indole-3-acetic acid (IAA)/ abscisic acid (ABA), cytokinin (CTK)/ abscisic acid (ABA) increased ultimately. These results of the experiments made sure that the accumulation of growth hormone and the degradability of control hormone was correlative to the germination of Cyclocarya paliurus seeds.