【摘要】 大豆是实行水旱轮作的重要作物之一,在缺乏良好排水条件的水田中实行水旱轮作时,长期涝渍所致的伤害成为大豆生长不良及产量低的重要原因。通过盆栽和大田试验在大豆生育初期进行过湿处理,调查培土或无培土条件下不定根的发生情况,揭示不定根对伤流速度,氮素的吸收运转等的影响,讨论了不定根与大豆耐湿性的关系。淹水条件下培土对不定根及根瘤的发生产生较大的影响,淹水条件下发生的不定根的量占总根重的43.1%,这些不定根提供了81.4%的伤流速度。不定根的呼吸速度为2.61mgCO2g-1h-1,是初生根的近3倍。淹水导致全叶位叶片的叶色变淡,不定根的发生改变了伤流液中不同形态氮素的组成和全氮含量,可使下位叶的叶色维持较高水平。淹水条件下大豆的冠根比比对照小。不定根取代了受涝渍伤害而失去功能的初生根的作用,积极地进行养分和水的吸收,确保了涝渍逆境下物质生产的顺利进行。更多还原

【Abstract】 Excessive soil water is often a serious problem in Jianghan Plain,which is a major marketable grain production base in Hubei Province,with continuous rainfall and poorly drained upland field which converted from paddy.As an important pioneer crop planted in the upland field converted from paddy,injury of excessive soil water become the main problem of low productivity of soybean.Waterlogged conditions were conducted at the early growth stage of soybean in pilot pot and in field experiments to survey the status of the incidence of adventitious roots under the conditions of ridging or no ridging,and to reveal the effect of adventitious root on xylem bleeding rate,nitrogen uptake and translocation in xylem bleeding sap and moisture resistance.Ridging had a greater influence on the incidence of adventitious root and root nodules than seedling age under the condition of flooding.The volume of adventitious root induced by flooding and ridging accounted for 43.1% of the total root weight,and accounted for 81.4% of bleeding rate.Respiration rate of adventitious root was 2.61 mg CO2 g-1 h-1,which was three times of the primary roots.Flooding treatment brought the SPAD of all the leaves in a plant down significantly,but adventitious root could revise the existent forms of nitrogen and total nitrogen content in xylem bleeding sap,and maintain the color of lower leaf on a higher level.The ratio of shoot to root under the condition of flooding was smaller than that of control.Therefore,as an adaptation character of soybean plants to excessive soil water,adventitious root was induced in a large number and replaced the function of primary root to assure dry matter production,thereby enhancing the flooding resistance of soybean plants.更多还原