• ISSN 1008-505X
  • CN 11-3996/S
徐新翔, 侯昕, 贾志航, 王芬, 葛顺峰, 姜远茂. 适量稳定供钾促进苹果矮化砧M9T337幼苗生长和氮素吸收利用[J]. 植物营养与肥料学报, 2020, 26(3): 552-560. DOI: 10.11674/zwyf.19177
引用本文: 徐新翔, 侯昕, 贾志航, 王芬, 葛顺峰, 姜远茂. 适量稳定供钾促进苹果矮化砧M9T337幼苗生长和氮素吸收利用[J]. 植物营养与肥料学报, 2020, 26(3): 552-560. DOI: 10.11674/zwyf.19177
XU Xin-xiang, HOU Xin, JIA Zhi-hang, WANG Fen, GE Shun-feng, JIANG Yuan-mao. Continuous and constant supply of potassium in suitable level stimulates the growth and absorption and utilization of nitrogen in M9T337 dwarf rootstocks seedlings[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(3): 552-560. DOI: 10.11674/zwyf.19177
Citation: XU Xin-xiang, HOU Xin, JIA Zhi-hang, WANG Fen, GE Shun-feng, JIANG Yuan-mao. Continuous and constant supply of potassium in suitable level stimulates the growth and absorption and utilization of nitrogen in M9T337 dwarf rootstocks seedlings[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(3): 552-560. DOI: 10.11674/zwyf.19177

适量稳定供钾促进苹果矮化砧M9T337幼苗生长和氮素吸收利用

Continuous and constant supply of potassium in suitable level stimulates the growth and absorption and utilization of nitrogen in M9T337 dwarf rootstocks seedlings

  • 摘要:
    目的 钾在氮代谢中发挥重要作用,通过同位素示踪技术,研究供钾水平和稳定性对苹果矮化砧M9T337幼苗生长及氮素吸收利用的影响,以深化理解钾素水平对苹果氮素吸收利用的影响机制,为苹果生产上科学施钾提供理论依据。
    方法 以苹果矮化砧M9T337幼苗为试验材料进行砂培试验,总处理周期为60天。以Hoagland营养液为基础,设置5个供钾处理,分别为持续低钾 (K 0.5 mmol/L,K1)、1~30天低钾 (0.5 mmol/L) 和31~60天高钾 (12 mmol/L,K2)、适量稳定供钾 (6 mmol/L,K3)、1~30天高钾 (12 mmol/L) 和31~60天低钾 (0.5 mmol/L,K4)、持续高钾 (12 mmol/L,K5)。每3天更换一次营养液,每次在营养液中加入0.01 g Ca(15NO3)2,共加入0.2 g。于处理后第31天和第60天取样,测定幼苗生长、根系性状以及氮素吸收利用分配状况。
    结果 供试苹果砧木幼苗处理第60天,以适量稳定供钾处理K3的生物量最大,根系总长、总表面积最大,根系活力也显著高于其他处理。31~60天,K2处理地上部干重增幅最大 (174.8%),K4处理根系干重增幅最大 (176.3%),幼苗总生物量、根系长度、根系总表面积增量最大的处理为K3 (依次为12.99 g/株、1059 cm/株和1113 cm2/株)。第31天和第60天两次测定结果显示,幼苗根部NO3吸收速率均以K3处理最大,分别为29.63和36.19 pmol/(cm2·s);K1、K4处理幼苗根部NO3离子流在第31天时为内流,在第60天时变为外排。整个处理期内,硝酸还原酶 (NR) 活性均以K3处理最高;处理41~60天,K2处理幼苗NR活性显著升高,而K4处理则显著降低。15N示踪结果表明,K3处理下苹果砧木幼苗对氮素的吸收能力最强,植株总吸氮量、15N利用率和叶片15N分配率均显著高于其他处理;处理第60天15N吸收量表现为K3>K5>K2>K4>K1。
    结论 持续的低钾、高钾以及变换性的高低钾处理会抑制苹果幼苗根系生长以及氮素向地上部运移,不利于氮素的吸收利用。而持续适宜稳定地供钾可以提高根系活力和硝酸还原酶活性,保持根系较高的NO3吸收速率,同时促进氮素由根系向叶片的运移,实现对氮素的高效吸收利用,从而促进苹果砧木幼苗的生长。

     

    Abstract:
    Objectives Potassium plays an important role in nitrogen metabolism. The growth, nitrogen absorption and utilization of apple were studied under different K supply conditions, which would help further understanding the influencing mechanism of potassium nutrition on nitrogen metabolism and providing support for reasonable K fertilization in apple production.
    Methods Sand culture method was used, and M9T337 dwarf rootstocks seedlings were used as materials and the culture lasted 60 days. At the base of Hoagland solution, K was supplied in five ways: deficient (0.5 mmol/L, K1) in 1–60 days, deficient (0.5 mmol/L) in 1–30 days and excess (12 mmol/L) in 31–60 days (K2), appropriate (6 mmol/L) in 1–60 days (K3), excess (12 mmol/L) in 1–30 days and deficient (0.5 mmol/L) in 31–60 days (K4), excess (12 mmol/L) in 1–60 days (K5). The nutrition solution was replaced every other three days, and 0.01 g of Ca(15NO3)2 was added into each pot with the replacement of solution and 0.2 g was added in total. At the 31st day and 60th day of treatment, seedling samples were collected for the measurement of growth, root traits, N content, root NO3 flux and seedling nitrate reductase (NR) activity.
    Result At the 60th day after treatment, K3 obtained the highest plant dry matter, the largest total root length and surface area, and significantly higher root activity. From 31 days to 60 days, the greatest increase of above-ground dry weight was in K2 treatment (174.8%), the largest increase of root dry weight was in K4 treatment (176.3%) and the greatest increase in total biomass, root length and root surface area were in K3 (12.99 g/plant, 1059 cm/plant and 1113 cm2/plant, respectively). In both the measurements at 31 days and 60 days, the highest root absorption rates of NO3 were all in K3 treatment 29.63 and 36.19 pmol/(cm2·s), respectively. In treatments K1 and K4, the NO3 ion flow in root was inward from day 1 to day 30 and became outward from day 31 to day 60. During the whole treatment period, K3 treatment had the highest NR activity; during 41–60 days, the NR activity increased significantly in K2 treatment but decreased significantly in K4. The results of 15N tracer showed that the N absorption ability of seedlings under K3 treatment was the highest, in which the seedling total N accumulation, 15N utilization rate and 15N allocation rate in leaf were all significantly higher than those in other treatments. At the 60th day after treatment, the total 15N absorption was in order of K3>K5>K2>K4>K1.
    Conclusions Deficient, excess or varied K supplement all impede root growth and nitrogen movement to shoot in apple seedlings, and are not conducive to nitrogen uptake and utilization. Constant and appropriate K supply will improve root activity and nitrate reductase activity, maintain a high NO3 uptake rate of root system, and promote the upward transport of nitrogen. So the constant and suitable K supply should be considered through fertilization for the healthy and efficient growth of apple rootstock seedlings in practical K management.

     

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