黄芪种子萌发的基础温度与积温需要——一种模型方法

为研究黄芪种子萌发的基础温度与积温需要,采用不同方式破除黄芪种子硬实后进行种子萌发试验,利用模型方法确定种子萌发的基础温度Tb、种子调整累积萌发率达到50%所需要积温θT(50%)及其标准差δθT等参数;同时根据达茂地区气候特点,设置不同起始温度(3.5℃、6.5℃、10.5℃),模拟不同春播时间(3月15日、3月25日、4月5日),对积温模型进行验证。结果表明,砂磨20min能有效打破黄芪种子硬实,提高种子发芽率;种子萌发的基础温度Tb=0.2℃,种子调整累积萌发率达累积萌发达到50%所需要的积温值θT(50%)=1 129.7℃.h(47℃.d),标准差δθT=18.34℃.h;各起始温度下种子调整累积萌发率达到50%的萌发时间分别为244、165、115h,相应出苗日期为3月26日、4月3日和4月11日。因此,考虑到达茂地区温度条件,播种期可以定在3月25日左右。

Basal Temperature and Thermaltime Requirement for the Germination of Astragalus membranaceus Seeds:A Modeling Approach

The present study investigated the base temperature and the thermaltime requirment for germination of Astragalus membranaceus seeds.After using different treaments to get rid of seeds hard,we determined the basal temperature(Tb),the thermaltime(θT),and the standard deviation of the thermaltime(δθT) by seeds germination test in different constant temperature conditions.Then we established the thermaltime model for seeds germination according to a modeling approach and verified it by culturing seeds in sand at different started temperature(3.5 ℃,6.5 ℃,10.5 ℃) following the local climate characteristics(March 15,March 25,April 5) of Damao.The results showed that: treating Astragalus membranaceus seeds with sand in 20 min can effectively break the seeds hard and promote germination percentage;seeds had a basal temperature of 0.2 ℃ and required approximately 1 129.7 ℃·h(47 ℃·d) to reach 50% under optimal water conditions;seeds adjusted cumulative germination time to 50% from different started time are 244 h,165 h,115 h,and the seeds emergence date are March 26,April 3 and April 11 correspondingly.Considering the temperature conditions in Damao,the seeds sowing date can be set in around March 25.