鹅观草种子萌发及出苗特性

Characterization of Seed Germination and Seedling Emergence of Roegneria kamoji Ohwi

在实验室和温室条件下研究不同温度、光照、水势、盐分对鹅观草种子萌发以及埋土深度对鹅观草出苗的影响。结果表明,鹅观草种子萌发的昼/夜温度范围为20℃/10℃~35℃/25℃,最适昼/夜温度为25℃/15℃;黑暗条件下,鹅观草种子萌发率较光照下略有提高,说明鹅观草萌发不需要光照;鹅观草种子对水势胁迫较敏感,水势从0下降至-0.8 MPa时,发芽率从93%直线下降至0;鹅观草种子对盐分胁迫具有一定耐受性,当NaCl浓度≤50 mmol/L时,种子均能保持80%以上的萌发率。50%萌发抑制率时的水势和NaCl浓度分别约为-0.4 MPa和100 mmol/L。埋土深度为0.5 cm时,鹅观草出苗率最高,埋土深度≥3 cm时出苗率显著下降。表明鹅观草种子萌发具有较强的环境适应性,通过耕作将其种子带入4 cm以下土层,可有效抑制鹅观草的危害。

Laboratory and greenhouse experiments were conducted to study the effects of temperature,light,osmotic and salt stress on seed germination,and the effect of burial depth on seedling emergence of Roegneria kamoji Ohwi. The temperature range for germination is 20/10 ℃~35/25 ℃,with the optimal day/night temperature 25 ℃/15 ℃. Under dark conditions,germination rate increased slightly,indicating that light was not necessary. Seed germination was sensitive to osmotic stress,and when the water stress dropped from 0 to-0.8 MPa,the germination rate decresedfrom 93% to 0. The seed could tolerate salt stress. When NaCl concentration is lower than 50 mmol/L,seed germination rate can be maintained at over 80%. The osmotic potential and NaCl concentration required for 50%inhibition of maximum germination were-0. 4 MPa and100 mmol/L,respectively. The seedling emergence rate was highest when the burial depth was 0. 5 cm,and it was significantly inhibited when the burial depth was over 4 cm. These results indicated that R. kamojihad relatively strong environmental adaptability,potentially becoming a competitive weed in wheat field. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence may enable effective control of this weed.