摘要
【目的】明确低氮胁迫对7种苹果砧木生长及生理生化特性的影响,为耐低氮苹果砧木的选育和氮高效吸收利用生理机制的研究提供理论依据。【方法】沙培试验以改良1/2 Hoagland营养液为基础,设定硝态氮含量正常水平(NN,5 mmol/L NO3–)和低氮胁迫(LN,0.5 mmol/L NO3–)两个处理,供试苹果砧木包括矮化砧T337、Nic29、Pajam2、B9、71-3-150和半矮化砧青砧2号、乔化砧山定子(Malus baccata L.Borkh.),均为一年生健康苗。处理60天后,测定砧木新稍生长、物质积累、根系形态、叶片和根系硝酸还原酶活性、植株氮累积量,利用隶属函数模糊评价法比较不同苹果砧木的耐低氮能力。【结果】在正常供氮条件下,乔化砧山定子的植株总干重和氮利用效率明显高于其他5种矮化砧;矮化砧中Pajam2的植株干物质积累量最大,B9的根冠比最高;矮化砧Nic29的新梢生长速率和叶片硝酸还原酶(NR)活性显著高于其余6种砧木;半矮化砧青砧2号的根系NR活性显著高于其余砧木,有利于植株的氮累积。与正常供氮相比,低氮条件下,T337、Nic29和山定子的新稍生长均受到显著抑制;B9、Pajam2和青砧2号的新稍生长未受明显影响;而71-3-150的新稍生长速率提高,叶面积增大,根系中干物质积累量增加,植株根冠比显著增大,为正常供氮处理的2.59倍。低氮条件下,T337、B9、Pajam2和山定子根系总表面积和总根长均显著降低,T337降幅最大;而71-3-150的根系总表面积、总根长、根系总体积、根尖数等根系参数显著升高;Nic29的根系总表面积、总根长和根总体积升高,但根尖数减少,根系分枝数也升高。低氮胁迫条件下,苹果砧木叶片NR活性减小,B9、Nic29、Pajam2和山定子根系中NR活性较正常供氮分别提高了3.70、5.16、2.85和5.14倍。低氮条件下,T337、B9、Pajam2和青砧2号的叶片、茎干和根系中氮累积量均趋于降低,植株氮累积量减小,青砧2号降幅最大,但B9、Nic29、Pajam2和青砧2号的氮利用效率均显著提高,青砧2号的增幅最大;而71-3-150的根系和植株氮累积量均显著升高。基于7种苹果砧木生长、根系参数、氮代谢酶活性、氮累积量和氮利用效率等19个指标的耐低氮胁迫指数,结合隶属函数模糊评价法和聚类分析将7种砧木分为3种耐性类型:第Ⅰ类为耐性强的砧木(71-3-150);第Ⅱ类为耐性较弱的砧木(Nic29、山定子、B9和青砧2号);第Ⅲ类为耐性最弱的砧木(Pajam2和T337)。【结论】在正常供氮条件下,乔化砧木山定子和半矮化砧青砧2号在植株干物质积累、根系发育和养分吸收利用等方面均强于矮化砧,但其对低氮胁迫适应性较弱。低氮条件下,苹果砧木通过提高氮利用效率适应养分亏缺,耐性强的砧木植株生长受抑制程度较小,并通过调节自身生理特性,增加根系中的物质和养分积累,提高植株根冠比,以适应低氮环境。
【Objectives】The tolerance of seven apple rootstocks to low nitrogen stress was studied for the selection and breeding of apple rootstocks.【Methods】Using the sand culture method,1/2 Hoagland nutrient solution as basic nutrient solution,normal N supply(NN,5 mmol/L NO3–) and low N stress(LN,0.5 mmol/L NO3–) were imposed.Seven annual apple rootstocks were tested―dwarf root stocks T337,Nic29,Pajam2,B9,71-3-150;semi-dwarf rootstock Qingzhen 2,and vigorous stock(Malus baccata L.Borkh.).After the rootstocks were treated for 60 days,the growth of new shoot,biomass accumulation,root morphology,nitrate reductase activity of leaf and root,as well as nitrogen accumulation were measured.The tolerance to low nitrogen stress in apple rootstocks was evaluated by membership function fuzzy evaluation method.【Results】Under normal N supply,the dry weight of total plant,root/shoot ratio,and nitrogen use efficiency of the vigorous stock M.baccata L.Borkh.were significantly higher than those of the five dwarf rootstocks,Pajam 2 had the highest dry matter accumulation in total plant and B9 had the highest root/shoot ratio among the dwarf rootstocks.The growth rate of new shoot and leaf NR activity of Nic29,a dwarf rootstock,were significantly higher than that of the remaining six rootstocks.The root nitrate reductase activity of the semi-dwarf Qingzhen 2 was significantly higher than that of the other rootstocks,which facilitated the nitrogen accumulation in root and plant.Compared with the normal N supply,the growth of new shoot in T337,Nic29 and M.baccata L.Borkh.was significantly inhibited under sub optimum nitrogen condition;the growth of new shoot in B9,Pajam2 and Qingzhen 2 was not significantly affected;while the growth of new shoot in 71-3-150 was significantly higher,the leaf area increased,the root biomass accumulation increased and the ratio of root/shoot increased significantly,reaching 2.59 times that of the control.Under N deficiency condition,all root parameters of T337,B9,Pajam2 and M.baccata L.Borkh.were significantly reduced,with T337 exhibiting drastic decrease,while root parameters such as total root surface area,total root length,total root volume and number of root tips increased significantly in 71-3-150,and total root surface area,total root length,root volume and root branches increased in Nic29,but the number of root tips decreased in Nic29.The leaf nitrate reductase activity of apple rootstocks decreased under nitrogen deficiency condition,and increased by 3.70,5.16,2.85 and 5.14-times in root of B9,Nic29,Pajam2 and M.baccata L.Borkh.,respectively,compared with normal nitrogen supply.Under nitrogen deficiency condition,nitrogen accumulation in leaves,stems,and roots of T337,B9,Pajam2 and Qingzhen 2 decreased,so as nitrogen accumulation in total plant decreased,with the largest decrease in Qingzhen 2.However,nitrogen use efficiency of B9,Nic29,Pajam2 and Qingzhen 2 all increased significantly,with the largest increase in Qingzhen 2,and nitrogen accumulation in both root and plant of 71-3-150 all increased significantly.The seven apple rootstocks were classified into three tolerance types based on tolerance index to nitrogen deficiency of above nineteen indicators,including the growth rate of new shoot,root parameters,nitrate reductase activity,nitrogen accumulation and nitrogen use efficiency,combined with the fuzzy evaluation method of the affiliation function and cluster analysis:Class I was the most tolerant rootstock(71-3-150);Class II was the less tolerant rootstock(Nic29,M.baccata L.Borkh.,B9 and Qingzhen 2);Class III was the least tolerant rootstocks(Pajam2 and T337).【Conclusions】Under normal nitrogen supply,the vigorous stock M.baccata L.Borkh.and the semidwarf Qingzhen 2 outperformed the dwarf rootstocks in terms of biomass accumulation,root development and nutrient uptake and utilization,but they were less adaptable to nitrogen deficiency condition.Apple rootstocks adapt to nitrogen deficiency by increasing nitrogen use efficiency,of which the tolerant rootstocks were less inhibited in growth and adapt to nitrogen deficiency conditions by regulating their own physiological characteristics,increasing biomass and nutrient accumulation in root,and improving the ratio of root/shoot.
作者
解斌
安秀红
陈艳辉
程存刚
赵德英
康国栋
周江涛
李壮
张艳珍
杨安
李鑫
XIE Bin;AN Xiu-hong;CHEN Yan-hui;CHENG Cun-gang;ZHAO De-ying;KANG Guo-dong;ZHOU Jiang-tao;LI Zhuang;ZHANG Yan-zhen;YANG An;LI Xin(Research Institute of Pomology,Chinese Academy of Agricultural Sciences/Key Laboratory of Fruit Germplasm Resources Utilization,Ministry of Agriculture and Rural Affairs of China/Key Laboratory for Efficient Utilization of Deciduous Fruit Mineral Nutrition and Fertilizer,Liaoning Province,Xingcheng,Liaoning 125100,China;Research Center for Agricultural Engineering Technology of Mountain District of Hebei/Mountainous Areas Research Institute,Hebei Agricultural University,Baoding,Hebei 071001,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2022年第6期1092-1103,共12页
Journal of Plant Nutrition and Fertilizers
基金
中国农业科学院科技创新工程(CAAS-ASTIP)
国家现代苹果产业技术体系(CARS-27)
国家重点研发计划项目(2016YFD0201100)
河北省高等学校科学研究项目(QN2020231)。
关键词
苹果砧木
低氮胁迫
根系形态
氮吸收利用
氮代谢
apple rootstock
nitrogen deficiency stress
root morphology
nitrogen absorption and utilization
nitrogen metabolism
