Conservation of gene diversities in plant populations with a mixed sexual and asexual reproduction system

方差有效大小是根据种群的阶段特定参数定义的，种群由多个人口统计学阶段组成，有性繁殖或无性繁殖。将该方程应用于具有复杂生活期、在一般生境条件下通过球茎分散进行无性繁殖的多年生草本植物camtschatensis的2个种群，估计其有效种群规模比（Ne/N）小于0.3左右，长期保护所需的种群规模大于几千。对一些虚构的人口统计学参数和生殖参数组合进行了数值计算，结果表明，在一定的种群规模N下，招募率较高、成熟个体持续时间较短的物种或群体往往具有较大的Ne/N，从而保持较高的遗传多样性。通过数值计算讨论了控制种群和繁殖变量的保护遗传效应，并将其归纳为四点；首先，幼体存活率的提高导致了Ne/N的增加；其次，向较高（更发达）阶段的加速过渡往往会增加较高阶段个体的Ne/N和相对分数；第三，成年（成熟）个体持续时间的延长降低了Ne/N和幼体的分数；第四，在许多多年生草本物种中观察到，成年（成熟）个体向幼体阶段的回归降低了Ne/N，但没有引起阶段分数的变化。

The variance effective size was defined in terms of stage-specific parameters of populations which are composed of multiple demographic stages, reproducing either sexually or asexually. Applying the equations to two populations of a perennial herb species F.camtschatcensis which has a complex life cycle and reproduces asexually by dispersion of bulbs in ordinary habitat conditions, the effective to census size ratio (Ne/N) and the population size required for long-term conservation were estimated to be less than about 0.3, and larger than a few thousands, respectively. Numerical computations of the equations for some fictious combinations of the demographic and reproductive parameters revealed that species or populations with a higher recruitment rate with shorter persistence of mature individuals tend to have a large Ne/N,and consequently, maintain a higher genetic diversity with a given census size N.This trend was observed between the two populations of F.camtschatcensis surveyed. Conservation genetic effects of controlling the demographic and reproductive variables were also discussed by the numerical computations to be summarized into four points ; first, increased survival rate of juveniles causes increase in Ne/N,second, accelerated transition to higher (more developed) stages tends to enlarge Ne/N and relative fractions of individuals of higher stages, third, longer persistence of adult (mature) individuals lessens Ne/N and the fraction of juveniles, and tourth, regression of adults to juvenile stage as observed in many perennial herb species acts to decrease Ne/N without causing any change in the fractions of the stages.