水培条件下火龙果根系形态和生理过程对供磷水平的响应  

Response of Root Morphology and Physiological Process of Pitaya[Hylocereus undatus(Haw.)Britt.et Rose]to Phosphorus Supply Level under Hydroponic Conditions

作　　者：高翔 杨永志 李娟[1] 陈思如 阮云泽[1] 高伟[1] GAO Xiang;YANG Yongzhi;LI Juan;CHEN Siru;RUAN Yunze;GAO Wei(College of Tropical Crops,Hainan University,Haikou,Hainan 570228,China)

机构地区：[1]海南大学热带作物学院,海南海口570228

出　　处：《热带作物学报》2024年第5期944-954,共11页Chinese Journal of Tropical Crops

基　　金：海南省自然科学基金高层次人才项目“火龙果磷高效利用的根系形态与生理过程研究”(No.321RC459);国家自然科学基金青年科学基金项目(No.32202586);海南省教育教学改革研究项目“新农科背景下产学研用、校企合作协同育人模式的探索与实践”(No.Hnjg2022-6)。

摘　　要：磷是作物生长必需的大量元素,参与体内重要生理生化过程。火龙果是热带、亚热带地区重要经济作物,高额的果实磷含量和巨大的产量使得火龙果对磷的需求量极高。然而,火龙果磷吸收特性以及根系形态和生理过程与磷高效吸收之间有何关系尚不清楚。本研究以国内主要火龙果品种软枝大红为研究对象,采用水培实验,设定0、0.01、0.1、0.5、1.0 mmol/L共5个不同磷浓度梯度,探究不同施磷浓度下火龙果根系形态和生理过程的变化,分析地上部磷以及其他营养元素的含量,阐明磷高效利用的根系形态和生理过程机制以及供磷对火龙果其他营养元素吸收的影响规律。研究结果表明,与对照相比,供磷并未影响火龙果地上部生物量的积累。火龙果枝条磷吸收量及磷浓度随着供磷浓度的升高而增大。0.1 mmol/L处理的总根长以及直径≤0.05 mm的细根数量显著高于其他处理;1.0 mmol/L处理的总根长中直径≥2 mm的粗根数量高于其他处理。0.01 mmol/L处理总有机酸含量最高,根系阳离子交换量(cation exchange capacity)含量较高;与对照相比,1.0 mmol/L处理下有机酸分泌速率降低,根系阳离子交换量(CEC)含量下降。其他营养元素吸收方面,母枝及一级侧枝中,铁元素的吸收浓度表现出随着施磷浓度的升高逐渐下降。二级侧枝中氮、钙、镁、锰、锌等元素均随着施磷浓度的升高逐渐下降,呈显著负相关关系。本研究表明,适度供磷(0.01 mmol/L或0.1 mmol/L)能够促进火龙果根系生长以及根系有机酸分泌和离子吸收能力,而过量供磷(1.0 mmol/L)会显著抑制火龙果根系生长,同时显著降低地上部枝条中、微量元素的吸收。因此合理施用磷肥,对火龙果自身发挥根系生物学潜力,为植株中、微量元素营养均衡起到关键作用。Phosphorus(P)is an essential macro-element for crop growth and is involved in critical physiological and biochemical processes in plants.Pitaya is an important economic crop in tropical and subtropical regions.High fruit P concentration and huge yield require high P demand for pitaya growth.However,the P absorption characteristics of pitaya and the relationship of root morpho-physiological processes and P uptake are still unclear.In this study,pitaya variety Soft Dahong,which is the most popular cultivar in China,was used.Five P gradients of 0,0.01,0.1,0.5 and 1.0 mmol/L were set by hydroponic experiment to explore the changes of root morphology and physiological process of pitaya under different P application rates.At the same time,the content of phosphorus and other nutrient elements in the aboveground part were analyzed to clarify the mechanism of root morphological and physiological traits for efficient P use and the effect of P supply on other nutrients uptake in pitaya.The results showed that compared with no P,P fertil-izer application did not affect the accumulation of aboveground biomass.P uptake and P concentration of shoot in-creased with the P application rates.The total root length and the number of fine roots with diameter≤0.05 mm in low P treatment(0.1 mmol/L)were significantly higher than those of other treatments.High P supply inhibited root growth,showing that the total root length was the shortest,and the number of coarse roots with diameter≥2 mm was higher than that of other treatments.Low P(0.01 mmol/L)treatment had the highest total organic acid content and higher root CEC content.Compared with no P,the organic acid secretion rate and root CEC content decreased under high P supply(1.0 mmol/L).In terms of the absorption of other nutrient elements,the absorption concentration of iron in the mother branch and the primary branch decreased gradually with the increase of P rate.The contents of nitrogen,calcium,magne-sium,manganese and zinc in the second order branches decreased gradually with

关 键 词：磷 火龙果 根系形态 根系生理 养分吸收 

分 类 号：S667.9[农业科学—果树学]