珍稀濒危植物珙桐不同采收期的种子特性研究

首次比较研究了国家一级保护濒危植物珙桐不同采收时期的种子特性。结果显示:不同采收期每50粒珙桐果实的出种量最高为101粒,最低为53粒,平均80.78粒,变异系数19.43%;果实出种量不随采收时间的推迟而增长,这表明在相似生境条件下珙桐植株间的有性生殖是非同步的。各采收期珙桐果实的出籽率都非常低,最高仅为1.63%,由于种子包装格局与果皮包装格局资源损耗的相对独立性,提示果实表型特征与种子发育程度不存在相关性。测定分析不同采收期珙桐种子电导率,11月5日所采集的种子在9份样品中种子质量最高。而种子形态数据与百粒重却显示11月5日所采集的种子在这两方面最小,长19.85cm、宽4.94cm、厚2.95cm,百粒重18.82g,这表明珙桐种子形态大小不能反映种子质量的高低。用0.5%TTC溶液测定珙桐种子活力,实验结果显示不同采收期珙桐种子活力均达90%以上。

Studies on seed characteristics of endangered plant Davidia involucrata in different collection period

Seed characteristics of endangered plant Davidia involucrata which were collected in different period were studied from the aspects of fruit output,seed production rates,pericarp water content,seed water content and seed conductivity. We measured and analyzed the data of seed phenotypic characters and 100-seed weight,the result showed that the minimum,maximum,average plump seed number and variation coefficient of per 50 fruits of different collection period was 53,101,80.78 and 19.43% respectively. Seed output of the fruit didn’t increase along with the lengthen of its growth time,which indicated that under the same living environment,the sexual reproductions of different mother trees still kept the different development levels. The seed production rates of Davidia involucrata in different collection periods were very low(the maximum was only 1.63%),and the resource consumptions of seed package patterns and pericarp package patterns were independent relatively,so this clued that there was no relationship between morphological character of fruit and seed growth condition. Based on the data of seed conductivity,we found that the seed vigor of the fruits collected on 5th November among those nine samples reached the highest point. By analyzing the seed phenotypic characters and 100-seed weight,we concluded that the results of the fruits collected on 5th November were both smallest in the two study aspects. The two results demonstrated that the size of seed couldn’t reflect its quality. The viability of seed was tested by TTC(0.5%),and the results of seed dissection showed that vigor seeds of different collection period were all more than 90%.