呼伦贝尔草原大针茅和贝加尔针茅的生殖生长规律

摘要

采用无样方采样法,对内蒙古呼伦贝尔草原大针茅(Stipa grandis P.Smirn)和贝加尔针茅(Stipa baicalensis Roshev.)生殖分蘖株的生物量分配和生殖生长规律的比较分析,以期揭示2种针茅的生殖生长状况和资源分配策略,提高草地的合理利用.结果表明:大针茅和贝加尔针茅生殖分蘖株穗重随植株总重、植株高度、穗长增加而增加;穗长、生殖生长比率随植株高度增加而增加;每穗籽粒数随小花总量增加而增加;每穗籽粒重随穗重、穗长增加而增加,均呈现y=a+bx线性函数变化规律,达到显著或极显著水平.大针茅生殖器官穗生长速率b值和穗重百分比大于贝加尔针茅,而结实籽粒的生长速率b值,以及茎、鞘、叶重百分比均却小于贝加尔针茅.生殖分蘖株生殖器官穗构件与营养器官生物量分配比例呈负相关.表明在相同生长条件下,2种针茅具有相同的生殖生长和资源分配规律,采取了生存和生殖相权衡的资源分配调节策略,且贝加尔针茅种子生产的能力大于大针茅.%Biomass allocation and reproductive growth rules of reproductive tiller of Stipa grandis P. Smirn and Stipa baicalensis Roshev. were analyzed in Inner Mongolia Hulunber steppe to reveal the reproductive growth status and resource allocation strategies of two Stipa and to improve the optimal utilization of grassland. Results showed that the panicle weight of reproductive tillers of S. grandis and S. baicalensis increased with an increase of total plant weight, plant height and panicle height. The panicle length and the reproductive growth rate increased with an increase of plant height. The kernel number per panicle increased with an increase of total floret. The seed weight per panicle increased with an increase of panicle weight and height. It showed a linear function (y=a＋bx) variation. The growth rate b value of panicle and percentage of panicle weight in S. grandis was greater than that in S. baicalensis. The growth rate b value of seed grain, percentage of stem, sheath and leaf weight in S. grandis was less than that in S. baicalensis. Panicle modules of reproductive tillers and the biomass allocation were negatively correlated.There were the same reproductive growth and resources allocation regulations between S. grandis and S.baicalensis under the same growth conditions.