外源褪黑素对重茬胁迫下平邑甜茶幼苗元素吸收利用的影响.pdf

果树学报2023，40（8）：1572-1582Journal of Fruit ScienceDOI:10.13925/ki.gsxb.20230027外源褪黑素对重茬胁迫下平邑甜茶幼苗元素吸收利用的影响何晓龙，刘怀特，张纪冉，尚雨薇，周莎莎，李中勇，张学英，徐继忠*，梁博文*（河北农业大学园艺学院，河北保定 071000）摘要：【目的】探究外源褪黑素（melatonin，MT）对重茬胁迫下平邑甜茶（Malus hupehensis Rehd.）矿质元素吸收利用和生长的调控效应。【方法】以平邑甜茶实生苗为材料，采用盆栽试验，研究根施200 molL-1褪黑素溶液对重茬胁迫下平邑甜茶幼苗根、茎和叶中10种矿质元素含量、吸收、转移积累及分配的影响。【结果】外源褪黑素提高了重茬胁迫下平邑甜茶植株各部分干生物量，改变了各部分元素的含量，并且显著提高了植株对大量元素和微量元素的吸收，提升了各元素在根茎叶中分布的比例。Mantel检验结果表明，平邑甜茶植株中各矿质元素与各部分干质量均呈正相关。【结论】重茬胁迫下外源施用200 molL-1褪黑素不仅能调控矿质元素的吸收和积累，还能促进植株生长。关键词：平邑甜茶；褪黑素；重茬胁迫；养分吸收中图分类号：S661.1文献标志码：A文章编号：1009-9980(2023)08-1572-11收稿日期：2023-02-13接受日期：2023-04-20基金项目：河北省属高校基本科研业务费（KY2021054）；河北省自然科学基金项目（C2021204158）；国家现代农业产业技术体系资助项目（CARS-27）；河北省重点研发计划项目（21326308D-02-03）作者简介：何晓龙，男，在读硕士研究生，研究方向为果树栽培生理与生态Tel：19943537316，E-mail：*通信作者Author for correspondence.Tel：[phone]，E-mail:；Tel：[phone]，E-mail：Effects of exogenous melatonin on the uptake and utilization of nutrientsin Malus hupehensis seedlings under replant stressHE Xiaolong,LIU Huaite,ZHANG Jiran,SHANG Yuwei,ZHOU Shasha,LI Zhongyong,ZHANGXueying,XU Jizhong*,LIANG Bowen*(College of Horticulture,Hebei Agricultural University,Baoding 071000,Hebei China)Abstract:【Objective】Apple replant disease(ARD)is a common soil-borne disease that decreases plantgrowth,increases damage by predatory insects,and decreases apple yield and quality.Current researchon preventing and treating ARD mainly focuses on changes in the physical and chemical properties,me-tabolites,and microbial community structure of the rhizospheric soil.In contrast,few studies have fo-cused on plant mineral nutrient absorption.In the present study,we investigated the effects of exoge-nous melatonin on the absorption,utilization,and accumulation of mineral elements in Malus hupehen-sis Rehd.under replant stress in order to provide a theoretical basis and technical support for the preven-tion and treatment of ARD.【Methods】In a pot experiment,400 healthy M.hupehensis seedlings wereplanted in June,2021 at the innovation experimental base of Hebei Agricultural University(38 230 N,115 280 E).The seedlings were divided into four groups:plants grown in healthy soil(CK);melato-nin control,plants grown in healthy soil containing 200 molL-1melatonin(MCK),plants grown inreplant soil(ST),and plants grown in replant soil containing 200 molL-1melatonin(MST).Mela-tonin(200 molL-1)was supplemented every 7 days from June to October,2021.The growth and min-eral element contents of the seedlings were analyzed after 120 days of experienment.The indices includ-ed dry weight and mineral element concentration,absorption,transfer,accumulation,and distribution inroots,stems,and leaves.Finally,the Mantel test was used to analyze the correlation between the miner-，等：幼苗元素吸收利用的影响第8期苹果是世界四大主栽果树之一。目前，我国苹果栽培面积、总产量与出口量均占世界第一，已成为世界上最大的苹果生产和消费国1。然而，中国大多数主要产区的果树已经超过使用寿命，进入衰老阶段，目前约有70%的果园树龄超过20 a（年）2。受土地资源和栽培条件的限制，同样的土地通常被用于重复生产，在这种情况下，苹果再植病（apple re-plant disease，ARD）已经变得非常普遍2。ARD 是al element content and the dry weight in each part of the M.hupehensis seedlings.【Results】The exoge-nous melatonin significantly increased the dry weight of the roots,stems and leaves of M.hupehensisseedlings under replant stress compared with the ST plants,by 44.19%,67.63%and 81.67%,respective-ly.Additionally,the concentration of mineral elements differed significantly among treatments.Com-pared with the ST plants,the MST plants showed significantly increased the concentrations of N,P andMn in the roots and stems,and N,P,Ca,Mg and Mn in the leaves,as well as significantly decreased theconcentrations of Fe,Zn,Cu and B in the roots,K,Fe and B in the stems,and Fe,Zn and Cu in theleaves.The replant stress significantly inhibited the absorption of the macroelements N,P,K,Ca,andMg by 74.04%,56.46%,61.17%,57.96%,and 56.50%,respectively,as well as that of the microele-ments Fe,Zn,Cu,Mn,and B by 49.49%,54.28%,37.57%,46.05%and 58.91%,respectively,com-pared with the control plants.However,the application of the exogenous melatonin significantly re-duced this inhibition and promoted the plant nutrient absorption.In terms of the nutrient transfer and ac-cumulation,compared with the ST plants,the application of the exogenous melatonin under replantstress significantly increased the accumulation of N,P,and Mn in the roots by 34.52%,20.03%and23.73%,respectively,while it significantly decreased the accumulation of Fe,Zn and B by 25.34%,22.72%and 61.62%,respectively.Additionally,the exogenous application of melatonin affected thetransfer rate of these elements to the leaves and stems.The transfer rate of all the elements(except Band Zn)to the leaves and stems increased significantly.Regarding nutrient distribution,the applicationof the exogenous melatonin under replant stress increased the distribution ratio of almost all the ele-ments in the roots,stems,and leaves.Compared with the ST plants,the contents of N,P,K,Ca,Mg,Zn,Cu and Mn in the roots of the MST plants increased by 76.13%,59.62%,34.30%,43.43%,44.21%,3.17%,13.11%and 63.63%,respectively,while the contents of N,P,K,Ca,Mg,Fe,Zn,Cu,Mn and Bincreased by 73.78%,69.29%,48.74%,57.21%,69.46%,30.86%,36.49%,45.81%,121.08%and41.42%in the stems,and by 128.15%,119.16%,79.73%,95.63%,113.28%,12.81%,26.70%,47.85%,103.23%and 62.08%in the leaves,respectively.The Mantel test and Pearson correlation analy-sis showed that after 120 days of treatment,the mineral elements in M.hupehensis plants were positive-ly correlated with the dry weight of each part,and also showed positive correlation with each other.TheN content was significantly positively correlated with K,Ca,Mg,Zn and B contents.The P content wassignificantly and positively correlated with the Ca and Mg contents.The K content was positively corre-lated with Ca,Mg,Zn and B contents.Moreover,there were significant positive correlations betweenthe contents of Ca and Mg,Mg and Cu,Fe and Zn,Zn and B,and Cu and Mn.In addition,the dryweight of each plant part exhibited significant positive correlations with the N,P,K,Ca,Mg,Zn,and Bcontents,but not with the Fe,Cu or Mn contents.【Conclusion】The exogenous application of 200molL-1melatonin under replant stress would regulate the absorption and accumulation of mineral ele-ments,and promote plant growth.These findings would provide a theoretical framework for understand-ing how melatonin regulates the nutrient absorption of M.hupehensis seedlings under replant stress,aswell as a theoretical basis and technical information for preventing and treatingARD.Key words:Malus hupehensis Rhed.;Melatonin;Replant stress;Nutrient absorption何晓龙，等：外源褪黑素对重茬胁迫下平邑甜茶幼苗元素吸收利用的影响1573果树学报第40卷一种通过土壤传播的疾病，ARD的复杂症状降低了苹果的生长和生产力。再植后的苹果树木生长减慢，叶片变黄，节间明显缩短，根部变色，根尖坏死，根系生物量下降，最终导致植株死亡3。因此，重茬障碍也成了苹果种植产业健康发展亟待解决的难题。褪黑素（melatonin）是一种高度保守的吲哚类化合物，从牛松果体中首次分离得到4。作为一种新型的植物生长调节剂，褪黑素不仅参与提高种子发芽率5、调节开花6和延缓衰老7等多种发育和生理过程；还可以调节矿质元素的吸收和分配，进而增强植株对各种逆境胁迫的耐受性8。目前，防治各种重茬障碍的应用研究主要关注根际土壤理化性质、代谢物质和微生物群落结构的改变9-11，以及对土壤微域环境和植株性能的影响等方面，有关植株对矿质养分吸收的报道较少，尤其是外源褪黑素对重茬胁迫下植株生长与养分利用关系的相关研究还较为缺乏。近年来，有研究发现外源褪黑素能够通过提高土壤酶活性、改变微生物群落结构来改善土壤环境，进而促进苹果植株的生长12。然而能否通过施用外源褪黑素来促进重茬胁迫下植株养分的吸收与利用还值得进一步研究。因此，笔者在本研究中以平邑甜茶实生苗为试材，探究外源褪黑素对重茬胁迫下平邑甜茶幼苗矿质元素氮（N）、磷（P）、钾（K）、钙（Ca）、镁（Mg）、铁（Fe）、锌（Zn）、铜（Cu）、锰（Mn）和硼（B）吸收利用的影响。利用不同处理间矿质养分利用的差异和植株生长的关系，阐明外源褪黑素对苹果重茬障碍的调控机制，也为苹果重茬障碍的防治提供理论依据和技术支持。1材料和方法1.1试验设计本试验于河北农业大学创新试验园（38230 N，115280 E）进行。重茬土取自河北省保定市30 a（年）的老果园，健康土壤取自邻近老果园周围的麦田土，从地表移除树叶和其他松散物质后，从多个随机选择的地点收集土壤，深度为540 cm，使用前将土壤混匀并过6 mm筛。试验材料为平邑甜茶（Malus hupenensis Rehd.）实生苗。无融合生殖型平邑甜茶种子来自于山东平邑（3570 N,117250 E）。首先将种子充分浸湿后与细沙混匀，然后在4 的条件下低温层积处理50 d，种子萌发后，在每个装有基质的营养钵中播种4粒种子并将其置于具有自然光照和温度条件下的温室中培养。当幼苗长到68枚真叶时，将其转移到高17.6 cm、上口径26.5 cm、底径23 cm的塑料透气花盆中。研究中褪黑素的浓度与文献12一致。在充足的水分和光照条件下生长30 d后，400株健康一致的平邑甜茶幼苗被平均分为4组：正常对照，植株生长在健康土壤中（CK）；褪黑素对照，植株生长在添加200 molL-1褪黑素的健康土壤中（MCK）；重茬胁迫处理：植株生长在重茬土壤中（ST）；重茬胁迫处理+褪黑素，植株生长在添加200 molL-1褪黑素的重茬土壤中（MST）。从2021年610月，每7 d进行1次褪黑素处理，共处理120 d。1.2测定指标及方法1.2.1生长指标的测定干质量的测定：在试验结束之前，从每个处理中收获整株植物，并将其分为根、茎和叶部分。所有植物样品在自来水、蒸馏水和超纯水中洗涤擦干后于105 杀青30 min，65 烘干至恒质量；然后用分析天平称量各部分干质量。1.2.2矿质元素浓度的测定将植株根、茎和叶的各部分干样磨碎混匀，过1 mm筛，采用H2SO4-H2O2和HNO3-H2O2消解法，全量N、P元素浓度用连续流动分析仪（AA3;SEAL Analytical,Norderstedt,Ger-many）测定；全量K、Ca、Mg、Fe、Zn、Cu、Mn、B等元素含量用电感耦合等离子体质谱（iCAP Q ICP-MS;Thermo Fisher Scientific,Waltham,MA,USA）测定。1.2.3矿质元素吸收、转移（积累）和分配量的测定矿质元素吸收量、转移量和分配量根据梁博文等13的公式计算。矿质元素吸收量：植株根、茎和叶各部分的干质量对应组织的元素浓度相对生长速率（relativegrowth rate，RGR）。矿质元素转移（积累）量：（M120-M0）（lnW120-lnW0）/（W120-W0）/（T120-T0）。其中M代表植株体内各元素总含量，W代表根干质量，T代表处理时间。矿质元素分配量：植株根、茎、叶各部分的干质量对应组织的元素含量。2结果与分析2.1重茬胁迫下外源褪黑素对植株生长的影响从表1中看出，与对照相比，ST处理下平邑甜茶1574，等：幼苗元素吸收利用的影响第8期幼苗根、茎、叶各部分的干质量均显著降低，分别下降了48.24%、50.29%和58.12%；与ST相比，MST处理下平邑甜茶幼苗各部分的干质量均显著升高，分别升高了44.19%、67.63%和81.67%。2.2重茬胁迫下外源褪黑素对植株矿质元素浓度的影响试验处理120 d后，测定并分析了植株根、茎、叶各部分矿质元素含量。如表2所示，与对照相比，重茬胁迫显著降低了根中N和B的含量,分别降低了42.47%和11.63%；但Ca、Mg、Fe、Zn、Cu和Mn的含量显著升高，分别升高了17.85%、33.91%、21.03%、20.52%、47.14%和70.01%；对P和K的含量没有显著影响。与重茬胁迫处理植株相比，重茬胁迫下施加外源褪黑素显著升高了根中N、P和Mn的含量，分别升高了21.77%、10.26%和13.33%；显著降低了Fe、Zn、Cu 和 B 的 含 量，分 别 降 低 了 30.91%、28.58%、21.70%和63.84%；但对K、Ca和Mg的含量无显著影响。表 2重茬胁迫下外源褪黑素处理 120 d 对平邑甜茶幼苗根中矿质元素浓度的影响Table 2Effects of exogenous melatonin treatment for 120 days on concentration of nutritional elements in roots ofM.hupehensis seedlings under replant stress处理TreatmentCKMCKSTMSTw（N）/（mgg-1）5.510.24 a4.950.42 a3.170.18 c3.860.08 bw（P）/（mgg-1）1.090.03 b1.090.04 b1.170.22 b1.290.04 aw（K）/（mgg-1）3.700.12 a3.610.19 a3.820.01 a3.560.12 aw（Ca）/（mgg-1）3.810.05 b4.090.09 ab4.490.17 a4.450.25 aw（Mg）/（mgg-1）1.150.03 b1.300.02 b1.540.12 a1.540.05 aw（Fe）/（gg-1）1 196.5466.33 b1 019.4927.98 c1 448.2138.85 a1 000.5140.40 cw（Zn）/（gg-1）9.550.68 b9.660.98 b11.510.23 a8.220.18 bw（Cu）/（gg-1）11.371.97 b12.800.42 b16.730.59 a13.101.15 bw（Mn）/（gg-1）27.411.20 d60.521.77 a46.602.95 c52.812.86 bw（B）/（gg-1）16.430.10 a10.800.23 c14.521.27 b5.250.52 d表 1重茬胁迫下外源褪黑素处理 120 d 对平邑甜茶幼苗生长的影响Table 1Effects of exogenous melatonin treatment for 120days on the growth of M.hupehensis seedlings under replantstress处理TreatmentCKMCKSTMST根干质量Root dry mass/g9.970.80 a11.871.17 a5.160.50 c7.440.14 b茎干质量Stem dry mass/g3.480.32 a4.050.44 a1.730.10 c2.690.07 b叶干质量Leaf dry mass/g5.730.05 a6.820.80 a2.400.39 c4.360.20 b注：数据由平均值标准差组成，3 次重复，同行不同小写字母表示存在显著差异（p0.05）。CK 表示植物生长在健康土壤中；MCK 表示植株生长在添加 200 molL-1褪黑素的健康土壤中；ST 表示植株生长在重茬土壤中；MST 表示植株生长在添加 200 molL-1褪黑素的重茬土壤中。下同。Note:Data are means standard deviation(n=3).Bars not labeledwith same letter indicate significant differences at p0.05,based onTukey s multiple range tests.CK,plants grown with control soil;MCK,plants grown in control soil with 200 mol L-1melatonin;ST,plants grown in replant soil;MST,plants grown in replant soil with200 molL-1melatonin.The same below.如表3所示，重茬胁迫同时能够影响茎中矿质元素的含量，显著降低了茎中N、Fe和Zn的含量，分别降低了15.64%、21.01%和23.47%；并显著升高了Ca和B的含量，分别升高了10.23%和17.18%；但对P、K、Mg、Cu和Mn含量没有显著影响。与重茬胁迫处理植株相比，重茬胁迫下施加外源褪黑素显著升高了茎中N、P和Mn的含量，分别升高了11.83%、9.38%和 42.29%；显著降低了茎中 K、Fe 和 B 的含量，分别降低了 4.08%、15.73%和 8.96%，但对 Ca、Mg、Zn和Cu含量没有显著影响。重茬胁迫还改变了叶中矿质元素的含量，如表4所示，与生长在健康土壤中的植株相比，重茬胁迫显著降低了叶中N的含量（27.71%）；但P、Ca、Fe、Zn和Cu的含量显著升高，分别升高了20.34%、5.58%、73.55%、53.64%和1.74%；对K、Mg、Mn和B的含量无显著影响。与重茬胁迫处理植株相比，重茬胁迫下施加外源褪黑素显著升高了叶中N、P、Ca、Mg和Mn 的含量，分别升高了 25.43%、20.42%、7.64%、17.67%和11.80%；显著降低了Fe、Zn、Cu的含量，分别降低了37.95%、30.32%和18.62%；但对K和B的含量无显著影响。2.3重茬胁迫下外源褪黑素对平邑甜茶幼苗矿质元素吸收的影响如图1-AE所示，与生长在健康土壤中的植株相比，重茬胁迫显著降低了植株对大量元素N、P、K、Ca 和 Mg 元素的吸收，其分别降低了 74.04%、何晓龙，等：外源褪黑素对重茬胁迫下平邑甜茶幼苗元素吸收利用的影响1575果树学报第40卷56.46%、61.17%、57.96%和56.50%。但施加外源褪黑素能够显著缓解这种抑制作用，重茬胁迫下施加外源褪黑素植株的吸收量只分别降低了41.61%、11.13%、32.83%、19.50%和14.20%。重茬胁迫同时也显著抑制了植株对微量元素的吸收(图1-FJ)。与对照植株相比，重茬胁迫对微量元素Fe、Zn、Cu、Mn 和 B 的吸收量分别降低了 49.49%、54.28%、37.57%、46.05%和58.91%。但在重茬胁迫下施加外源褪黑素能够显著促进植株对其的吸收，与ST植株相比，MST 植株的吸收量分别升高了 16.15%、36.21%、40.47%、101.09%和36.07%。2.4重茬胁迫下外源褪黑素对平邑甜茶幼苗矿质元素转移和积累的影响如图2所示，重茬胁迫处理显著影响了大量元素和微量元素在根中的积累量，与生长在健康土壤中的植株相比，重茬胁迫植株根中Mg、Fe、Zn、Cu和 Mn的积累量分别升高了17.38%、2.87%、4.95%、29.86%和51.64%，但N、K和B的积累量分别显著降低了51.46%、10.29%和23.84%。重茬胁迫下施加外源褪黑素能够显著提高根中N、P和Mn的积累量，分别升高了34.52%、20.03%和23.73%，并显著降低了 Fe、Zn 和 B 的积累量，分别下降了 25.34%、22.72%和61.62%。另外，重茬胁迫还影响了矿质元素向叶片和茎中转移的速率，除B和Zn元素外，N、P、K、Ca、Mg、Fe、Zn和Cu向叶片和茎中转移的速率均显著降低。此外，与在重茬土壤中生长的植株相比，外源施加褪黑素也影响了上述元素向叶片和茎中转移的速率，除B和Zn元素无显著影响外，其余元素向叶片和茎中转移的速率均显著升高。2.5重茬胁迫下外源褪黑素对平邑甜茶幼苗矿质元素分配的影响处理120 d后，矿质元素在根、茎、叶中的分配各不相同，其中P、K、Fe、Cu和Mn的含量在根中最高，N、Ca、Mg和Zn的含量在叶中最多，而B在茎中的分布最多（图3）。如图3所示，重茬胁迫处理后所有测定元素在根茎叶的比例均显著降低，与正常对照植株相比，ST植株根、茎、叶中N、P、K、Ca、Mg、Fe、Zn、Cu、Mn和B的含量分别下降了70.3%、58.17%、69.73%，44.45%、47.96%、49.58%，46.65%、52.08%、59.12%，39.09%、45.26%、55.74%，30.45%、52.42%、57.87%，37.44%、60.77%、27.27%，37.69%、61.99%、35.62%，23.52%、58.20%、14.96%，12.11%，53.21%、60.09%和54.31%、41.8%、52.26%。此外重茬胁迫下外源施加200 molL-1褪黑素能够增加几乎所有研究元素在根茎叶中分布的比例。与生长在重茬土壤中的植株相比，MST植株根中 N、P、K、Ca、Mg、Zn、Cu、Mn的含量分别提高了76.13%、59.62%、34.30%、43.43%、44.21%、3.17%、13.11%和63.63%，茎中N、表 3重茬胁迫下外源褪黑素处理 120 d 对平邑甜茶幼苗茎中矿质元素浓度的影响Table 3Effects of exogenous melatonin treatment for 120 days on concentration of nutritional elements in stem ofM.hupehensis seedlings under replant stress处理Treat-mentCKMCKSTMSTw（N）/（mgg-1）6.010.28 a5.660.31 a5.070.06 b5.670.11 aw（P）/（mgg-1）0.920.01 b0.930.03 b0.960.03 b1.050.03 aw（K）/（mgg-1）3.820.02 a3.750.09 ab3.680.14 ab3.530.08 bw（Ca）/（mgg-1）11.340.33 b10.840.16 b12.500.21 a12.660.23 aw（Mg）/（mgg-1）1.360.06 a1.320.04 a1.310.04 a1.310.04 aw（Fe）/（gg-1）233.683.14 a229.765.92 a184.597.52 b155.554.62 cw（Zn）/（gg-1）23.051.60 a19.992.46 ab17.641.13 bc15.500.27 cw（Cu）/（gg-1）7.290.28 a6.880.23 a6.140.38 a5.760.07 aw（Mn）/（gg-1）15.680.41 c22.680.76 a14.780.39 c21.030.27 bw（B）/（gg-1）42.791.39 b44.473.04 b50.141.68 a45.650.66 ab表 4重茬胁迫下外源褪黑素处理 120 d 对平邑甜茶幼苗叶片中矿质元素浓度的影响Table 4Effects of exogenous melatonin treatment for 120 days on concentration of nutritional elements in leaves ofM.hupehensis seedlings under replant stress处理Treat-mentCKMCKSTMSTw（N）/（mgg-1）10.500.77 a10.720.77 a7.590.32 b9.520.19 aw（P）/（mgg-1）1.180.05 c1.250.12 bc1.420.03 b1.710.03 aw（K）/（mgg-1）5.660.11 a5.770.11 a5.520.18 a5.460.07 aw（Ca）/（mgg-1）11.650.28 c11.420.05 bc12.300.20 b13.240.38 aw（Mg）/（mgg-1）2.480.04 b2.510.01 b2.490.03 b2.930.02 aw（Fe）/（gg-1）169.654.06 b175.634.54 b294.4219.01 a182.685.78 bw（Zn）/（gg-1）17.730.40 bc15.530.28 c27.242.48 a18.980.49 bw（Cu）/（gg-1）4.020.11 c4.040.27 c11.010.30 a8.960.27 bw（Mn）/（gg-1）32.671.02 ab27.351.05 c31.110.82 b34.781.08 aw（B）/（gg-1）27.012.09 a29.622.13 a30.772.01 a27.431.85 a1576，等：幼苗元素吸收利用的影响第8期数据由平均值标准差组成，3 次重复，不同小写字母表示存在显著差异（p0.05）。CK 表示植物生长在健康土壤中；MCK 表示植株生长在添加 200 molL-1褪黑素的健康土壤中；ST 表示植株生长在重茬土壤中；MST 表示植株生长在添加 200 molL-1褪黑素的重茬土壤中。下同。Data are means standard deviation(n=3).Within a row,values not followed by the same letters indicate significant differences at p0.05,basedon Tukey s multiple range tests.CK,plants grown with control soil;MCK,plants grown in control soil with 200 molL-1melatonin;ST,plantsgrown in replant soil;MST,plants grown in replant soil with 200 molL-1melatonin.The same below.图 1重茬胁迫下外源褪黑素处理 120 d 对平邑甜茶幼苗矿质元素吸收的影响Fig.1Effects of exogenous melatonin treatment for 120 days on uptake fluxes of nutritional element in M.hupehensisseedlings under replant stress氮吸收通量Uptake fluxes of N/（mgplant-1d-1）磷吸收通量Uptake fluxes of P/（mgplant-1d-1）钾吸收通量Uptake fluxes of K/（mgplant-1d-1）钙吸收通量Uptake fluxes of Ca/（mgplant-1d-1）镁吸收通量Uptake fluxes of Mg/（mgplant-1d-1）铁吸收通量Upt