用渗透剂胁迫鉴定谷子芽期耐旱性的方法研究

Methods for Identification of Drought Tolerance at Germination Period of Foxtail Millet by Osmotic Stress

采用PEG-6000、甘露醇2种渗透剂7种渗透势模拟水分胁迫,以谷子芽期发芽率、芽长、根长的相对值作为鉴定评价指标,研究谷子芽期耐旱性鉴定的水分胁迫条件。结果表明:在胁迫强度较弱时,40%谷子品种萌发、80%谷子品种胚芽、胚根的生长表现促进作用;在胁迫强度较强时,表现出抑制作用。在PEG-6000、甘露醇胁迫下,萌发耐旱指数与种子千粒重呈负相关,与相对发芽势主要表现为中度正相关,与相对根/芽比主要表现为负相关(PEG-6000胁迫),与相对芽长、相对根长相关系数很小;相对芽长与相对根长的相关关系主要表现为中度正相关。种子萌发耐旱指数与相对根长两个指标宜作为谷子芽期耐旱性鉴定指标,-0.75MPa PEG-6000、-1.00MPa甘露醇处理可以作为谷子芽期耐旱性鉴定的水分胁迫条件。

Using polyethylene glycol（PEG） -6000 and mannitol with osmotic potential from -0.25MPa to -1.50MPa for simulating water stress, the relative germination rate （ germination drought resistance index, GDRI）, relative sprout length （RSL） and relative root length （RRL） were served as evaluation indexes, and the osmotica concentration for evaluation of drought resistance in foxtail millet was researched. The result indicated that germination rate of 40 percent of varieties, sprout growth and root growth of 80 percent of varieties were promoted under higher osmotic potential, and they were inhibited under lower osmotic potential. Under PEG-6000 or mannitol stress, the correlation was negative between GDRI and 1000-grain weight, and mostly positively moderate between GDRI and relative germinative energy （RGE） , and mostly negative between GDRI and the relative root/sprout （RR/S） （under PEG-6000） , and lower between GDRI and RSL or RRL; the correlation was mostly positively moderate between RSL and RRL. GDRI and RRL were selected for evaluation indexes; -0.75MPa PEG-6000 or -1.00MPa mannitol stress was proper condition for the evaluation of drought resistance at germination period in fox-tail millet.