松嫩平原碱化草甸朝鲜碱茅(Puccinellia chinampoensis)种群生殖分蘖株的生长规律

朝鲜碱茅(Puccinellia chinampoensis)是一种耐盐碱丛生型禾草,广泛分布于松嫩平原碱化草甸.采用每隔3d对朝鲜碱茅种群中处于抽穗初期的生殖分蘖株随机挂一次标签,于籽实蜡熟期同时进行大样本取样与测定的方法,定量分析了5次所标记的生殖分蘖株的数量性状的变化规律及生殖分蘖株的生长规律.结果表明,在朝鲜碱茅种群中,虽然抽穗时间只相隔3d,但生殖分蘖株的各数量性状均具有较大的表型可塑性,总的变化趋势是抽穗时间相隔越长,差异越大.其中,5次样本中的相邻平均花序生物量之间的差异均达到了显著水平.延长生殖生长16d,平均分蘖株高增加了23.16%,花序长增加了25.70%,分蘖株生物量增加了74.99%,花序生物量增加到2.63倍,生殖分配增加了93.25%.随着生殖生长时间的延长,朝鲜碱茅种群生殖分蘖株高、分蘖株生物量和花序生物量均呈指数增加,花序长和生殖分配呈直线增加,生殖生长比率呈先增加后降低的抛物线变化.不同时间进入生殖生长阶段的生殖分蘖株均具有相同的生长规律.其中,花序长均随分蘖株高的增加呈指数异速增长,花序生物量均随分蘖株生物量的增加呈直线同速增长.分蘖株的生殖生长越延长,对现实种群的贡献就越大,对未来种群的贡献更大.

Quantitative analysis of prolonged reproductive growth of the tillers of Puccinellia chinampoensis population in alkalized meadow in the Songnen Plains of China

It is a universal phenomenon that most individuals in a plant population flower in a relatively short period of time as influenced by photoperiod.Puccinellia chinampoensis is a salt-tolerant tuft grass.The flowering stage of P.chinampoensis populations lasts for about 20 days in alkalized meadow in the Songnen Plains of China,while the ripping stage lasts for only a few days.Large samples of reproductive tillers of P.chinampoensis population were randomly marked with labels every three days at the early earring stage,and the samples marked at five times were reaped together at the dough stage.The differences of the quantitative characters with time were compared among the five samples.Regressive analyses between the means of the quantitative characters and the time of prolonged reproductive growth,and correlation analyses between the growth and the production of every sample were made.The fitted equations with the highest R2 were selected from linear,power,exponential and quadratic functions as the models to describe the relationships.The early earring stage was defined as the date when spikes reached about one centimeter from top leaf.The reproductive growth stage was defined as the period from early earring to dough stage.The time of prolonged reproductive growth for each of the samples was defined as the time difference between its reproductive growth time and that of the last sample.Results of statistical analysis showed that there were significant differences among the five samples in spike biomass and the longer the reproductive growth time,the larger the variances of the quantitative characters,reflecting large phenotypic plasticity of the reproductive tillers in P.chinampoensis population.As the time of reproductive growth prolonged by 16 days,the mean height of tillers increased by 23.16%,and the mean length of spikes by 25.70%,the mean biomass of tillers by 74.99%,the mean biomass of spikes by 1.63 times and the mean reproductive allocation by 93.25%.Prolonged time of reproductive growth had a positive effect on the growth and production of tillers,especially the increase of spike biomass and the allocation of nutrients to spikes.Results of regressive analysis showed that tiller height,tiller biomass and spike biomass of P.chinampoensis population increased exponentially with the time of prolonged reproductive growth,and spike length and reproductive allocation increased linearly,while reproductive growth radio increased first and then decreased,namely a parabola pattern.By comparing increasing rate(coefficient) 'b' in the regressive equations,it was indicated that the assimilated products in the tillers were first allocated to the growth and development of spikes,and then to that of tillers.When the contributions to present population and future population were estimated by tiller biomass and spike biomass respectively,the longer the time of prolonged reproductive growth,the larger the contribution to present and future populations.There was the same growth regulation among the reproductive tillers in P.chinampoensis population with different earring dates.Spike length increased exponentially with tiller height in an allometry way,and spike biomass increased linearly with tiller biomass in an isogony way.Regular changes of increasing rate 'b' in the correlation equations indicated that there were orderly processes in the growth of tiller height and spike length,and matter production and transmission.When the five samples were combined and analyzed as one single sample,the regulating process of increasing rate was not detected.