白皮松种子休眠特性的种源变异

Variation of dormancy characteristic of different Pinus bungeana seed sources.

对7个具有代表性种源的白皮松种子的休眠特性研究表明,白皮松种子种皮的透水性在种源间差异明显,表现出随地理纬度的增高而逐渐增大的趋势,分布越是偏北的种源透水性趋于加强.根据种皮的透水性,7个种源可被分为差异明显的2组,组间以秦岭为界.不同种源种子种皮的透气性以外种皮造成的差异为最大,内种皮次之.种子的透气性与透水性表现出的变化趋势相同.不同种源种子浸提液的抑制能力显著不同,而且这种差异随浸提液浓度的增加而增加.依据种皮浸提液的抑制能力7个种源可分为2组,而依据胚乳浸提液的抑制能力则可被分为3组.种子的发芽能力有随纬度的增加而降低的趋势,种子发芽率越低的种源则其平均发芽时间也越长.依据不同标准所划分的种群组均表现出组间差异大于组内差异的特点,组间种源产地之间的距离也大于组内.白皮松种子休眠特性在种源间的差异是气候及地理因子共同作用的结果.

Studies on the dormancy characteristics of Pinus bungeana seeds from 7 representative seed sources show that the difference of water permeability of seed capsule was very significant among seed sources.The seeds from northern part of distribution area had a much higher water permeability than from the south.According to water permeability,the seven seed sources were divided into 2 geographical groups, with Qinling Mountain as the division line.The difference of seed ventilation was caused firstly by outer seed capsule,and secondly by inner one.The variation of permeability had a similar trend with the ventilation.The inhibition ability of seed extracts was significantly different among different seed sources,which was increased with the concentration of seed extracts.Based on the inhibition ability of extracts from seed capsule and endosperm,the seven seed sources were divided into 2 and 3 geographical groups,respectively.The germination capacity decreased with increasing latitude,and seeds with poor germination capacity took relatively more time for germination. All population groups based on different division criteria showed such a character,i.e., the difference of seed characteristics was more significant among groups than in same group,and the distance of seed source was longer among groups than in a group.The difference of dormancy characteristics of different P.bungeana seed sources was the result of interaction between climatic and geographical factors.