牧草间作对干旱胁迫下油橄榄根系形态特征的影响

Effects of pasture intercropping on root morphological characteristics of olive under drought stress

为了揭示干旱胁迫下间作牧草对油橄榄根系的影响,采用盆栽试验方法,设置4种水分条件(土壤含水量分别为18%、15%、12%、9%,以18%土壤含水量作为对照),各水分条件下以不间作为对照,油橄榄幼苗盆内分别进行3种间作牧草处理,即间作苜蓿、间作红三叶、间作苜蓿+红三叶。对油橄榄在牧草间作与干旱胁迫条件下的多个根系形态指标进行测定及相关性分析,并采用隶属函数法进行不同牧草间作处理下油橄榄的抗旱性比较。结果表明:(1)轻度水分胁迫促进油橄榄根系总长度和根系生物量的增大,干旱胁迫加剧则显著降低了根系的总根长、根平均直径、总表面积、总根体积,间作牧草后降低幅度减小。(2)间作牧草明显增加油橄榄根系生物量、比根长、比根面积,以间作红三叶处理最为显著。(3)随着土壤含水量减小,油橄榄根系组织密度增大,间作苜蓿和间作苜蓿+红三叶处理在重度干旱胁迫下高于不间作对照。(4)相关分析及隶属函数分析结果表明间作牧草能够增强油橄榄根系的耐旱性,间作红三叶处理的油橄榄根系抗旱性较强。

Pot-culture experiment was conducted to reveal the effects of pasture intercropping on olive roots under drought stress.Four water conditions(the soil water content was 18%,15%,12%and 9%)and three intercropping treatments(intercropping alfalfa,intercropping red clover,intercropping alfalfa+red clover)were set up in this study.The root morphological indices of olive under the conditions of different pasture intercropping and drought stress were measured,and the correlation was analyzed.In addition,the subordinate function method was used to compare the drought resistance of olive under different pasture intercropping treatments.The results showed that the increase of total root length and root biomass was promoted under mild water stress.With the increase of drought stress,the total root length,root average diameter,total surface area and total root volume of olive decreased significantly,while the decreasing range was reduced by intercropping pasture.The root biomass,specific root length and specific root area of olive were significantly increased by intercropping pasture.The effect of intercropping red clover was the most significant.With the decrease of soil water content,the root tissue density of olive increased.Moreover,the root tissue density in the treatments of intercropping alfalfa and intercropping alfalfa+red clover was higher than that in control under severe drought stress.The results of correlation analysis and subordinate function indicated that intercropping pasture could enhance the drought resistance of olive root,and it was stronger in the treatment of intercropping red clover.