白苞猩猩草种子萌发特性研究

Seed germination characters of Euphorbia heterophylla Linn.

白苞猩猩草（Euphorbia heteroph ylla Linn.）对川滇两省干热河谷区的旱坡地果园水果生产和栽培粮食作物（如玉米、甘薯）生产已构成严重威胁.本文探讨了光、温、水等环境因子对白苞猩猩草种子萌发的影响.研究结果表明,白苞猩猩草种子最适萌发温度为25～30℃,在高温45℃或低温5℃时不能萌发;白苞猩猩草种子在土壤相对含水量≥10％时即可萌发,并在20％时萌发率达到最大值71.3％;种子破土能力弱,种子位于土壤表层0 cm时,出苗率高达80.7％,覆盖6 cm以上土层能有效遏制其出苗;12 h光暗交替有利于种子萌发;中性或偏酸性、低盐度（0.02 mol/L NaCl）环境有利于种子萌发.本研究将为白苞猩猩草综合治理提供科学依据和途径.

Euphorbia heterophylla has been causing serious threats to orchard fruit production and crop produc- tion, including corn and sweet potatoes in dry and hot valleys of Sichuan and Yunnan. This study investigated the effects of various environmental factors, including light, temperature and soil moisture, on the seed germination of E. heterophylla. Our results revealed that the optimum temperature for seed germination was between 25- 30 ℃, and seeds could not germinate when temperature was below 5 ℃ or above 45 ℃ ; the seeds could germinate when soil relative water content （SRWC） was no less than 10% and the germination rate reached the maximum of 71.3% at SRWC of 20% ; the germination rate reached to 80.7% when the soil depth was 0 cm, while a covered soil of 6 cm in thickness or more effectively inhibited seed germinating; a photoperiod of 12 h was shown to be ad- vantageous for seed germination; and the neutral or weakly acidic conditions, and low salinity （0.02 mol/L NaCl） environment also favored seed germination. In conclusion, this study would provide scientific evidence for control- ling E. heterophylla spreading.