两个木薯品种需水特性研究

目的]探讨木薯品种华南205和新选048的需水特性,为木薯大田栽培及抗旱育种提供科学依据.方法]以广西木薯主栽品种华南205和广西大学自育品种新选048为材料,试验设置正常供水(A)、轻度干旱(B)、中度干旱(C)和重度干旱(D)共4个土壤水分处理,在木薯块根形成期(5~7月)、膨大期(7~9月)和成熟期(9~12月)测定木薯净光合速率、叶片水势、叶片膜透性、叶绿素a+b、丙二醛、脯氨酸以及生物产量等相关指标.结果]华南205表现出受胁迫时间要早于新选048.生育期越靠后,木薯受到水分胁迫的影响越显著.干旱条件下受到水分胁迫时,木薯叶片光合作用的效率受到影响,在中轻度干旱条件下还表现出一定的水分胁迫补偿效应.结论]木薯对于干旱胁迫响应的生理顺序为:光合速率>蒸腾>气孔导度>叶片水势,适当的水分胁迫有利于木薯产量的形成和淀粉积累;在该试验条件下,木薯品种新选048表现出比华南205更强的抗旱性及耐旱能力.

Water-requirement characteristics of two cassava varieties

【Objective】This experiment was conducted to discuss the water-requirement characteristics of cassava varieties SC 205 and Xinxuan 048 and to provide scientific basis for cassava cultivation and drought resistance breeding. 【Method】Cassava varieties SC 205 （main variety grown in Guangxi） and Xinxuan 048 （bred by Guangxi University） were taken as test materials； four treatments， viz.， （A） normal water supply （CK）， （B） mild drought， （C） moderate drought， and （D） severe drought， were set. The net photosynthetic rate， leaf water potential， leaf membrane permeability， chlorophyll a+b， MDA， PRO， and biomass were measured during the cassava root tube formation period （from May to July） and expanding period （from July to September）， and maturity（Sep. to Dec）. 【Result】The water-stress time of SC 205 was earlier than that of Xinxuan 048. The influence of water-stress on cassava was more obvious in the late growth period. The photosynthesis efficiency of cassava leaves was affected by water stress under drought condition. However， the compensation effect of water stress on the photosynthesis efficiency was likely to appear under the mild and moderate drought conditions. 【Conclusion】The order of cassava physiology responses to drought stress was as follows： photosynthetic rate> transpiration>stomatal conductance>leaf water potential. The appropriate water stress was beneficial to cassava yield formation and starch accumulation. Cassava variety Xinxuan 048 showed stronger drought resistance than that of SC 205 under this experimental condition.