Mycorrhizal colonisation and P-supplement effects on N uptake and N assimilation in perennial ryegrass under well-watered and drought-stressed conditions
Mycorrhizal colonisation and P-supplement effects on N uptake and N assimilation in perennial ryegrass under well-watered and drought-stressed conditions
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DOI：
10.1007/s00572-012-0430-6
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发表时间：
2012-02
期刊：
影响因子：
3.9
通讯作者：
Bok-Rye Lee;S. Muneer;J. Avice;W. Jung;Tae-Hwan Kim
中科院分区：
文献类型：
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作者：
Bok-Rye Lee;S. Muneer;J. Avice;W. Jung;Tae-Hwan Kim
为了比较丛枝菌根（AM）和磷补充对水分充足和干旱胁迫条件下N吸收和N同化的影响，将接种球囊霉（Glomus intraradices-colonized）、磷补充的非菌根（P）和非菌根（对照）的多年生黑麦草（Lolium perenne）植株暴露于12 d的水分处理中。在水分处理开始（第0天）和结束（第12天）时，测定叶片水势（WPW）、光合能力以及氮、磷营养状况。氮吸收，氨基酸和蛋白质合成定量使用同位素示踪剂15 N在第12天。在良好的浇水条件下，AM和P植物的生长反应和生理参数相似，与对照相比。干旱（10%的水）显着降低这些参数在所有三个处理。与对照相比，水分亏缺对AM植物的光合速率、生物量、氮磷含量的负面影响明显减轻，而对P植物的影响则略有改善或保持不变。在水分充足和干旱胁迫条件下，AM真菌共生对氮素吸收和同化的影响大于磷素补充，干旱胁迫条件下，AM真菌共生对氮素吸收和同化的影响更大。在终端干旱胁迫的第12天，AM定植对从头合成的氨基酸和蛋白质的影响是4.4和4.8倍，高于磷补充剂。这些结果表明，AM共生体在N营养中起着综合作用，通过减轻干旱对N或P吸收和N同化的负面影响，而在干旱胁迫条件下，直接补充P的效率是非常有限的。
To compare the effect of arbuscular mycorrhiza (AM) and P-supplement on N uptake and N assimilation under well-watered or drought-stressed conditions,Glomus intraradices-colonised, P-supplemented non-mycorrhizal (P) and non-mycorrhizal (control) plants ofLolium perennewere exposed to 12 days of water treatment. Leaf water potential (Ψw), photosynthetic ability, and N and P nutritional status were measured at the beginning (day 0) and end (day 12) of water treatment. N absorption, amino acid and protein synthesis were quantified using the isotopic tracer15N at day 12. Under well-watered conditions, growth response and physiological parameters were similar in AM and P plants, as compared to controls. Drought (10% water) significantly decreased these parameters in all three treatments. As compared to control plants, the negative impact of water deficit on theΨw, photosynthesis, biomass, and N and P content was highly alleviated in AM plants, while only slightly improved or remained the same level in P plants. The effect of AM symbiosis on N absorption and N assimilation was greater than that of the P supplement under well-watered and drought-stressed conditions, and this effect was highly enhanced under drought-stressed conditions. At terminal drought stress on day 12, the effect of AM colonisation on de novo synthesis of amino acids and proteins was 4.4- and 4.8-fold higher than that of the P supplement. These results indicate that the AM symbiosis plays an integrative role in N nutrition by alleviating the negative impacts of drought on N or P uptake and N assimilation, whereas the efficiency of a direct P supplement is very limited under drought-stressed conditions.