Abstract:

The research demonstrates variation and adaptive countermeasures of Quercus variabilis population through a discussion of its size, number of seedlings, characters differentiation and interior gene arrangement and offers the ecological strategies of Quercus variabilis population answering different habitats from mechanism. Both size and number of stump-sprouting vary from place to place seen from its distribution and the number of stump-sprouting is relatively less in Qinling distribution center, whereas almost every size class has a good few number of stump-sprouting on north slope of Bashan Mountain and Huanglong Mountain. These stump-sprouting offsets the shortage of seedlings, and help Q. variabilis population get through the pinch period thus regenerate themselves. At the same time, the branch length, ramification angle, ramification ratio, allele frequencies and differentiation coefficients of Q. variabilis population give birth to variance. From distribution center to margin, the branch length that every year diminishes while ramification angle and leaf obliquity takes on increscent trend, gradual ramification ratio R_1∶2, R_2∶3 and total ramification ratio R_b are also distinctly different. Gene variance frequencies of EST and SOD gradually diminish with that of POD gradually diminish along with age class augment, whereas the differentiation coefficients of EST, SOD, PGI, ACP and ADH wear increscent trend. These changes are adaptive response that Q. variabilis population reply to environments, and thereby, open out the ecological strategies and evolutional mechanism of Q. variabilis population.

Key words: Quercus variabilis, population, variation, adaptive countermeasures