Colimitation of phytoplankton growth by nickel and nitrogen
Colimitation of phytoplankton growth by nickel and nitrogen
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DOI：
10.4319/lo.1991.36.6.1071
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发表时间：
1991-09
影响因子：
4.5
通讯作者：
N. M. Price;F. Morel
中科院分区：
文献类型：
--
作者：
N. M. Price;F. Morel
Shalussiosiru M；Eissflgii的无菌培养需要镍，当尿素是生长的氮源时，但当在NH上生长时，没有可测量的镍需求。这一结果是由于含有镍的酶--尿素酶所致。这是这种硅藻中尿素分解代谢所必需的。在缺镍培养中，尿素是氮素的唯一来源，尿素酶活性低，生长速度减慢。在富镍培养中，尿素酶活性增强，达到最大生长速度。尿素生长的细胞对镍的饱和吸收速率比NH++生长的细胞的饱和吸收速率快，并且在限制镍的条件下增强。镍限制的T.Weiss&‘ogii细胞也受到氮的限制，即使在培养液中有高浓度的尿素，因为它们没有足够的尿素酶活性来提供足够的氮来生长。因此，在这些培养物中，最大生长速率是通过供应镍或NH+来获得的。这些结果证明了在实验室条件下，镍和氮对T.M.eissflogjii生长的共生作用，并提供了一个可能适用于其他营养素的痕量金属和常量营养素相互作用的原型例子。
Axenic cultures of Thalussiosiru M;eissflogii need nickel when urea is the source of nitrogen for growth, but have no measurable Ni requirement when growing on NH,‘. This result is due to the Ni-containing enzyme, urease. which is necessary for urea catabolism in this diatom. In Ni-deficient cultures, where urea is the sole source of N, urease activity is low and growth rate is reduced. In Ni-replete cultures, urease activity is enhanced and the maximum growth rate achieved. Saturated uptake rates of Ni by urea-grown cells are faster than by NH,+-grown cells and are enhanced under Ni-limiting conditions. Ni-limited T. weiss&‘ogii cells are also N limited, even with high concentrations of urea in the medium, because they have insufficient urease activity to provide adequate N for growth. In these cultures, maximum growth rates are thus obtained by supplying either Ni or NH,+. These results demonstrate colimitation of T. M;eissflogjii growth by Ni and N under laboratory conditions and provide an archetypal example of a trace metal and macronutrient interaction that may be applicable to other nutrients.