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河北地区8月中旬黄顶菊可产生具有萌发力的种子。9月上、中旬黄顶菊开花3～5 d即可产生具萌发力的种子。此时产生的种子成熟进度最快、所需日度最少。9月中旬至10月初,黄顶菊种子成熟度最高,萌发率达94%以上。10月黄顶菊进入末花期,开花20 d内完成种子成熟过程,但种子萌发率低于20%。9月25日前开花的黄顶菊,种子达到50%发芽率所需有效积温随开花始期递减。黄顶菊植株初花期是对其防治的最晚时期,7月底至8月初为河北地区黄顶菊最晚防治适期。
In mid-August, flaveria bidentis can produce germinated seeds. In September, middle and mid-yellow florescence flowering 3 ~ 5 d can produce seeds with germination. At this point the seed matures fastest, requiring the least day. From mid-September to early October, Flaveria bidentis seeds had the highest maturity and the germination rate was over 94%. In October, the florescence entered the final flowering stage, and the seed maturation was completed within 20 days of flowering, but the seed germination rate was less than 20%. Flaveria bidentis that bloomed before Sept. 25, the effective accumulated temperature needed to achieve 50% seed germination, decreased with the initial period of flowering. The first flowering stage of flaveria bidentis is the latest stage of its prevention and treatment, and the late stage of prevention and control of flaveria bidentis in Hebei from the end of July to the beginning of August.