Root plasticity and its functional roles were triggered by water deficit but not by the resulting changes in the forms of soil N in rice
Root plasticity and its functional roles were triggered by water deficit but not by the resulting changes in the forms of soil N in rice
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DOI：
10.1007/s11104-014-2240-4
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发表时间：
2014
期刊：
影响因子：
4.9
通讯作者：
Thiem Thi Tran;Mana Kano‐Nakata;R. Suralta;D. Menge;Shiro Mitsuya;Y. Inukai;A. Yamauchi
中科院分区：
文献类型：
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作者：
Thiem Thi Tran;Mana Kano‐Nakata;R. Suralta;D. Menge;Shiro Mitsuya;Y. Inukai;A. Yamauchi
研究背景水稻根系可塑性在适应干旱条件下的作用因土壤氮素条件的不同而不同。目的：研究轻度干旱胁迫和施氮促进水稻根系可塑性发育是否有助于提高土壤吸水率，以及不同形态氮素对根系可塑性的表达是否有影响。在根箱(25 cm × 40 cm × 2 cm)试验中，施氮量分别为30(低)、60(标准)和120 mg(高)，在盆栽(5个L)试验中，6种氮素形态(单独的NH_4+-N、单独的NO_3−-N、组合NH_4+-N和NO_3−-N)与双氰胺(硝化抑制剂)的用量均为360 mg/盆。然而，在干湿条件下，CSSL50的干物质生产(DMP)显著高于日本晴，这是因为CSSL50保持土壤水分吸收和光合作用的能力更强。CSSL50在WD条件下表现出较高的吸水率和光合作用，这与其可塑性促进根系发育密切相关，高N处理显著高于低N处理。不同氮素形态对根系发育的促进作用差异不显著。结论在施氮量较高的情况下，CSSL50对WD的根系可塑性有较大程度的表现，其根系可塑性对土壤吸水率和DMP的作用是由WD发挥作用的，而与氮素形态无关。
BackgroundThe functional roles of root plasticity in rice adaptation to drought conditions may vary with soil nitrogen (N) conditions.AimsTo examine if: promoted root system plastic development triggered by mild drought stress and enhanced by N application would contribute to the increase in soil water uptake, and if expression of root system plasticity would be affected by different forms of N applied into the soil.MethodsChromosome segment substitution line (CSSL) 50 and Nipponbare genotypes were grown under continuously waterlogged (CWL) and water deficit (WD) conditions. In rootbox (25 cm × 40 cm × 2 cm) experiment, three fertilizer N levels; (30 (low), 60 (standard) and 120 mg N (high) per rootbox) were used while in pot (5 L) experiment, six N forms (NH4+-N alone, NO3−-N alone, combined NH4+-N and NO3−-N with and without dicyandiamide (nitrification inhibitor) were used at the rate of 360 mg N per pot.ResultsIn both experiments, CSSL50 and Nipponbare had no significant differences in shoot and root growth regardless of N levels and N forms under CWL conditions. However, under WD conditions, CSSL50 had significantly greater dry matter production (DMP) than Nipponbare due to the greater ability of the former for maintaining soil water uptake and photosynthesis. The observed higher water uptake and photosynthesis in CSSL50 under WD was closely related to its promoted root system development due to plasticity, which were significantly greater at high N than at low N level. The extent of promotion in root system development based total root length was not significantly different among N forms.ConclusionsThe root system plasticity of CSSL50 in response to WD was expressed at a greater degree with high level of N applied and the functional roles of root plasticity for greater soil water uptake and DMP were due to WD regardless of N forms.