自然生境低温胁迫对留茬巨菌草再生特性的影响及再生能力评价

Field Evaluation of Response and Resistance to Regeneration of Stubble Pennisetum sp. After Low Temperature in Natural Habitat

【目的】为留茬巨菌草在砒砂岩区以及我国中部适宜地区自然条件下的越冬储备、高产稳产、高效利用提供科学依据。【方法】以留茬巨菌草为试验材料,测定不同自然生境低温胁迫后的出苗时间、出苗率、成苗率、出苗力指数、植株高度、分蘖数量、分蘖能力、茎粗、叶片长度、叶片宽度、叶片数量、地上部分含水量、鲜重、新根长度、新根数量、新根长度/株高的比值等再生特性,综合评价不同自然生境及其不同胁迫温度后留茬巨菌草的再生能力。【结果】随着胁迫温度降低,出苗时间增加,出苗率、成苗率、出苗力指数、植株高度、分蘖数量、分蘖能力、茎粗、叶片长度、叶片宽度、叶片数量、地上部分含水量、鲜重、新根长度、新根数量等降低,新根长度/株高的比值呈现"先下降后上升再下降"的趋势;不同自然生境再生能力强弱为:沟坝地>坡耕地;同一自然生境不同胁迫温度后再生能力强弱为:5℃>0℃>-5℃>-10℃>-15℃。【结论】为了确保其再生能力,提高经济效益,建议在冬季温度不低于0℃(胁迫积温大于-12℃)、土壤具有一定保水能力的地区开展连茬多年生栽培。

【Objective】The present study was conducted to provide a scientific basis for the overwintering reserve,high yield,stable yield and efficient utilization of the stubble Pennisetum sp.in the Pisha sandstone areas and the suitable region in central China under natural conditions.【Method】To comprehensively evaluate the regeneration ability of stubble Pennisetum sp.after low temperature stress in different natural habitats,the regeneration characteristics as follows were studied:(i)Emergence index such as seedling emergence time,seedling emergence rate,seedling survival rate and seedling emergence index;(ii)Morphological index such as height,tiller number,tiller ability,stem diameter,leaf length,leaf width and leaves;(iii)Plant biomass such as the water content and fresh weight of aboveground part;(iv)Plant root such as new root length,new root number and the ratio of new root length to plant height,etc.【Result】Most of the indexes showed a downward trend except seedling emergence time and new root length/plant height ratio under the stress of temperature reduction.The seedling emergence time became longer while the new root length/plant height ratio showed a trend of first decrease then increase and decrease.Meanwhile,the regeneration ability of stubble Pennisetum sp.after low temperature stress in Dike field were stronger than in sloping farmland.The regeneration ability of stubble Pennisetum sp.in the same natural habitat under different stress temperatures was:5℃>0℃>-5℃>-10℃>-15℃.【Conclusion】In order to ensure the regeneration ability and improve the economic benefits of stubble Pennisetum sp.,it is suggested to carry out continuous cultivation in areas where the minimum temperature is higher than 0℃(stress accumulated temperatures are higher than-12℃)in winter and the soil has a certain extent of water retention capacity.