不同比例保水剂对干旱胁迫下红小豆幼苗生长的影响

Effects of Different Proportions of Water-Retaining Agents on Growth of Red Bean Seedlings under Water Stress

为找出干旱胁迫下适宜红小豆幼苗生长的最适保水剂拌土比例,进而为种植红小豆提供理论依据,试验采用盆栽试验的方法,以陕北红小豆为试验材料,根据保水剂不同拌土比例,设置了7个试验处理,分别为0(CK)、0.5%、1.0%、1.5%、2.0%、2.5%和3.0%,每个处理重复4次。前期正常管理,每盆加入相同量的水,在红小豆幼苗长到两叶一心时,最后一次浇透水,自然干旱12 d后测定红小豆幼苗的生长和生理生化指标,结果表明:在相同灌水量和相同干旱胁迫时间下,添加保水剂能够有效提高红小豆幼苗株高、茎粗、侧根数、最大根长的增加,尤其在保水剂拌土比例为1.5%时促进作用最强;随保水剂拌土比例的增加,除丙二醛(MDA)含量呈现先下降后上升趋势外,超氧化物歧化酶(SOD)、过氧化物酶(POD)、根系活力、叶绿素(Chl)、叶片相对含水量(RWC)均呈现出先上升后下降的趋势,且在保水剂拌土比例为1.5%时,其生理生化指标达到最大值。保水剂拌土比例为1.5%时,对红小豆幼苗期的生长效果最好。

To find out the optimal proportion of water-retaining agents suitable for the growth of red bean seedlings under drought stress for providing a theoretical basis for planting of red bean.A pot experiment was conducted with red bean planted in Northern Shaanxi as the experimental material,and seven treatments were set according to different soil proprotions of water-retaining agents,which included 0(CK),0.5%,1.0%,1.5%,2.0%,2.5%and 3.0%.Each treatment was repeated four times.At early stage of normal management,the same amount of water was added to each pot.When the red bean seedlings grew with one leaf,it was watered for the last time.After 12 days of natural drought,the growth,physiological and biochemical indexes of red bean seedlings were measured.Under the same amount of irrigation and the same drought stress time,the addition of water-retaining agent could effectively improve the increase of plant height,stem diameter,number of lateral roots and maximum root length of red bean seedlings.Especially,the promotion effect was the strongest when the proportion of water retaining agent was 1.5%;With the increase of water retaining agent,the content of malondialdehyde(MDA)decreased first and then increased,superoxide dismutase(SOD),peroxidase(POD),root activity,chlorophyll(CHL)and leaf relative water content(RWC)increased first and then decreased.When the water-retaining agent was 1.5%,its physiological and biochemical indexes reached the maximum.When the water retaining agent was 1.5%,the growth effect of red bean at seedling stage was the best.