摘要
【目的】探究不同供磷水平下根系分泌物对苹果砧木磷元素吸收的影响,为解决苹果园区普遍存在的有效磷易被固定为难溶态磷而导致的缺磷问题提供参考。【方法】以平邑甜茶(Malus hupehensis Rehd.)、八棱海棠(M.robusta Rehd.)、M26(M.pumila Mill.)、M9(M.pumila Mill.)、楸子(M.prunifolia)、中砧一号(M.xiaojinensis)、山丁子(M.baccata Borkh.)7种苹果砧木为试验材料,采用基质培养在正常供磷(对照)(0.5 mmol·L^(-1)KH_(2)PO_(4))、低磷(LP)(0.01 mmol·L^(-1)KH_(2)PO_(4))、额外施加磷酸钙(LP-Ca_(3)(PO_(4))_(2))[0.01 mmol·L^(-1)KH_(2)PO_(4)+Ca_(3)(PO_(4))_(2)]条件下处理50 d,测定7种苹果砧木的磷效率、根系分泌物、根系构型(root system architecture,RSA)、光合及荧光参数等指标,结合相关性及主成分分析探究根系分泌物对苹果砧木磷元素高效吸收的影响。【结果】与正常施磷相比,经低磷处理后,平邑甜茶、M26、M9、中砧一号的根冠比均显著提高,中砧一号的上升幅度为49.5%;除山丁子外其余6种砧木的光合速率均显著降低。在RSA方面,除根总表面积外其他3个指标均受低磷处理的显著影响。在柠檬酸分泌速率(citric acid secretion rate,CASR)方面,与正常施磷相比,低磷处理显著提高了除M26外其余6种砧木的分泌速率,中砧一号的CASR最高;经低磷处理后,苹果酸分泌速率(malic acid secretion rate,MASR)与CASR有着相似的变化规律,中砧一号的MASR显著高于除八棱海棠以外的其余5种砧木,M26在7种砧木中最低。【结论】供试的7种苹果砧木在低磷胁迫耐性方面存在显著差异。在低磷胁迫下,7种砧木根系的酸类物质分泌与磷吸收效率(phosphorus acquisition efficiency,PAE)呈正相关,中砧一号的PAE最高,其柠檬酸和质子分泌速率(proton secretion rate,PSR)也均高于其他6种砧木,同时其MASR也显著高于除八棱海棠以外的其余5种砧木。
【Objective】The aim of this study was to explore the effects of root exudates on the phosphorus acquisition efficiency of apple rootstocks under different phosphorus supply levels,so as to provide the theoretical basis for solving the common problem of phosphorus deficiency in apple orchards.An additional calcium phosphate treatment was also designed to investigate the effect of root exudation on alleviating phosphorus stress.【Methods】Seven kinds of apple rootstocks including Pingyi Tiancha(Malus hupehensis Rehd.),Baleng (M.robusta Rehd.),M26 (M.pumila Mill.),M9 (M.pumila Mill.),Qiuzi (M.prunifolia),Chistock-1 (M.xiaojinensis) and Shandingzi (M.baccata Borkh.) were used as experimental materials.The differences in tree growth,root exudates,root architecture,photosynthesis and fluorescence parameters,and phosphorus efficiency of each rootstock under normal phosphorus(CK)(0.5 mmol·L^(-1)KH_2PO_4),low phosphorus (LP)(0.01 mmol·L^(-1)KH_2PO_4),and additional calcium phosphate treatments (LP-Ca_3(PO_4)_2)(0.01 mmol·L^(-1)KH_2PO_4+Ca_3(PO_4)_2) for 50 days were studied.After 50 d,the plants were oven-dried for 72 h.The dried plants were digested using a microwave oven(Mars,CEM,USA).An inductively coupled plasma optical emission spectrometry (ICP-OES,Optima5300DV,Perkin Elmer,USA) was used to measure the phosphorus content.Root images were collected with an EPSON scanner and root total length,root surface area,root total volume and root tips were analyzed with the software Win RHIZO version 5.0 (Regent Instruments Inc.,Canada).The photosynthetic and fluorescence parameters of leaves were measured with a Li-6400 XT portable photosynthetic measurement system (Li-Cor Biosciences,Lincoln,USA).The effects of root exudates on phosphorus acquisition efficiency of apple rootstocks were investigated by correlation and principal component analysis.All experiments had eight biological replicates.Statistical analyses were performed using IBM SPSS Statistics (Version 25,SPSS,Chicago,IL,USA) and Origin software (2022,Origin Lab,Northampton,MA,USA).【Results】Compared with the normal phosphorus treatment,the root-shoot ratios of Pingyi Tiancha,M26,M9,and Chistock-1 were significantly increased under low phosphorus condition,and the increase rate of Chistock-1 was 49.5%.The root-shoot ratio of Shandingzi was the largest after additional application of calcium phosphate.Except for root total surface area,the other three root indexes were significantly affected by low phosphorus treatment.The root total length of Pingyi Tiancha,Baleng,M26 and M9 increased after low phosphorus treatment,of which Baleng increased by 37.5%compared with CK.Compared with normal phosphorus,the root total volume of Baleng and M26 increased significantly,and the number of root tips of Pingyi Tiancha,M9 and Chistock-1 increased significantly under low phosphorus treatment,and the increase rate of Chistock-1 reached 89.2%.Under low phosphorus treatment,the PAE of Chistock-1 was the highest.After additional application of calcium phosphate,the PAE of Chistock-1 and Shandingzi increased significantly compared with low phosphorus treatment,with an increase rate of 40%in Chistock-1.Low phosphorus treatment resulted in a significant decrease in the photosynthetic rate in Shandingzi leaves compared to CK.Low phosphorus treatment significantly increased citric acid secretion rate in the rootstocks except M26,and the citric acid secretion rate in Chistock-1 was the highest.After low phosphorus treatment,the change pattern of malic acid secretion rate was similar to that of the citric acid secretion rate.The malic acid secretion rate of Chistock-1 was significantly higher than that of the remaining rootstocks except Baleng.M26 was the lowest in malic acid secretion among the seven rootstocks.【Conclusion】The seven apple rootstocks tested differed significantly in their tolerance to low phosphorus stress.Under low phosphorus stress,the secretion of organic acids was positively correlated with the phosphorus acquisition efficiency of apple rootstocks.The phosphorus acquisition efficiency of Chistock-1 was the highest,and its citric acid and proton secretion rates were all higher than those of the other six rootstocks.At the same time,its malic acid secretion rate was significantly higher than that of the other rootstocks except Baleng.
作者
纪国翡
李梦珂
卢念
赵雪雯
苏泽彬
许雪峰
张新忠
韩振海
邱昌朋
JI Guofei;LI Mengke;LU Nian;ZHAO Xuewen;SU Zebin;XU Xuefeng;ZHANG Xinzhong;HAN Zhenhai;QIU Changpeng(College of Horticulture,China Agricultural University/Key Laboratory of Stress Physiology and Molecular Biology for Fruit Trees in Beijing Municipality,Beijing 100193,China)
出处
《果树学报》
CAS
CSCD
北大核心
2023年第11期2359-2370,共12页
Journal of Fruit Science
基金
国家重点研发计划项目(2019YFD1000103)
国家自然科学基金项目(31801810)
国家苹果产业技术体系项目(CARS-27)
农业农村部园艺作物营养与生理重点实验室
中国农业大学2115人才工程(00109023)
北京市教委高精尖学科建设项目(PXM2019_014207_000032)。
关键词
苹果砧木
低磷胁迫
磷酸钙
根系分泌物
有机酸
Apple rootstock
Low phosphorus stress
Calcium phosphate
Root exudates
Organic acid
