基于根系形态对磷吸收的贡献解析小麦||蚕豆间作促进磷吸收的作用

Contribution of root morphology to phosphorus absorption in wheat and faba bean intercropping system

间作模式是充分挖掘作物自身生物学潜力,促进磷资源高效利用的有效手段。为进一步探明间作诱导的根系形态适应性变化对磷吸收的相对贡献,理解小麦||蚕豆间作系统促进磷吸收的作用机制,本研究采用水培法,研究了常规磷(Hoagland营养液磷水平)和低磷(1/2-Hoagland营养液磷水平)条件下,小麦||蚕豆间作对小麦和蚕豆磷吸收、生长性状和根系形态变化的影响,并结合集成推进树算法(ABT)分析小麦和蚕豆根系形态对小麦和蚕豆磷吸收的相对贡献。结果表明,在低磷水平下,与单作小麦相比,小麦||蚕豆间作可以显著促进小麦对磷的吸收;而在正常磷水平下,间作小麦的磷吸收量显著低于单作小麦。在常规磷和低磷水平下,间作均能够显著促进蚕豆对磷的吸收。正常磷水平,间作系统的磷吸收量是小麦和蚕豆单作系统平均磷吸收量的1.04倍;低磷水平,间作系统的磷吸收量是小麦和蚕豆单作系统磷吸收量的1.28倍。种植模式和供磷水平能够显著影响小麦的株高,且有显著的交互作用;间作显著降低蚕豆的株高。ABT分析结果表明,小麦根长、根平均直径主导了小麦根系对磷的吸收,其解释量分别为74.7%和25.3%;蚕豆根长、根平均直径和根表面积共同解释了根系对磷的吸收,其解释量分别为48.0%、35.2%和16.9%。因此,低磷条件下,小麦||蚕豆间作主要通过增加小麦的根长,显著降低小麦根系平均直径,促进小麦对磷的吸收;而间作系统中的蚕豆则通过增加根长促进其对磷的吸收。

Intercropping is an effective way of enhancing efficient use of phosphorus resources through using the biological potential of crops.This study aims to explore the relative contribution of root morphological adaptations to phosphorus absorption under intercropping,and to explore how the wheat||faba bean intercropping system promotes phosphorus uptake.Wheat and faba bean were grown hydroponically under either adequate or deficient phosphorus levels.The effect of intercropping on their phosphorus uptake,growth traits,and root morphology were analyzed.The relative contribution of root traits to phosphorus uptake by wheat and faba bean were then analyzed using the aggregated boosted trees(ABT)method.Our results showed that under phosphorus deficient conditions,the uptake of phosphorus by wheat was higher in the wheat||faba bean intercropping system than in the monoculture.Conversely,phosphorus uptake by wheat under adequate phosphorus conditions was lower in the intercropping system.The uptake of phosphorus by faba bean was higher in the intercropping system than in the monoculture under both phosphorus conditions.The intercropping system led to a total phosphorus uptake that was 1.04 and 1.28 times higher than that of the corresponding monocrop system under adequate and deficient phosphorus conditions,respectively.This result indicated an advantage of intercropping over monocropping.Crop patterns and phosphorus availability resulted in significant effect in wheat height;interaction between these two factors was also observed(P<0.05).Intercropping led to a decrease in plant height for both species.The ABT analysis suggested that root length and diameter played a major role in phosphorus uptake by wheat,accounting for 74.4%and 25.3%uptake,respectively.Root length,diameter,and surface area all appeared to account for the uptake of phosphorus by faba bean,accounting for 48.0%,35.2%,and 16.9%uptake,respectively.To conclude,under phosphorus deficient condition,the improved phosphorus uptake by wheat in wheat||faba bean intercropping system was the result of an increase in root length and a decrease in root diameter,while the phosphorus uptake by faba bean was improved owing to an increase in root length.