组织培养获得的海黍子幼孢子体的营养盐吸收和生长特性的研究

Nutrient Uptaking and Growth Performance of Tissue Culture Generating Young Sargassum muticum Sporophyte

以组织培养间接获得的海黍子幼孢子体为实验对象，研究温度和氮、磷浓度对其营养盐吸收和生长的影响。结果显示，15-30℃范围内幼孢子体均可吸收NO3--N、NH4＋-N和PO43--P。25-30℃下NH4＋-N的吸收显著高于10～15℃时，而NO3--N和PO43--P的吸收速率在实验温度下差异不显著。NO3--N、NH4＋-N和PO43--P的最大吸收速率分别出现在15、25和25℃。当氮浓度〈3000μg·L^-1时，幼孢子体均可吸收NO3--N和NH4＋-N，且二者均呈现开放型吸收模式。当磷浓度〈30μg·L^-1时，幼孢子体可吸收PO2-P，且呈现饱和型模式。温度对幼孢子体的生长影响显著。10-30℃范围内，富含氮磷组和去除氮磷组的特定生长率（SGR）均随着温度的升高先增大后减小，且最大SGR（分别为19．58％·d^-1和14．58％·d^-1）在25℃时取得；叶绿素a、c的含量随着温度的升高先减小后增大。氮、磷浓度对幼孢子体的生长影响显著。富含氮磷组的SGR、叶绿素口含量和叶绿素C含量分别在15～25℃、15~30℃和20-30℃范围内显著高于去除氮磷组。

The effect of temperature and nutrient concentration on nutrient uptaking and growth perform- ance of tissue culture generating young Sargassum muticum sporophytes was determined in this study. The sporophytes were able to uptake NO3--N, NH4＋-N and PO43--P at temperatures ranging from 15 to 30℃. The uptaking rate of NH＋-N at temperatures ranging from 25℃ to 30 ℃ was significantly higher than that at temperatures ranging from 10 to 15℃. No significant effect of temperature on the uptaking rate of NO3--N and PO43--P was observed. The uptake rate of NO3--N, NH4＋-N and PO43--P reached their maxi- mum at 15, 25 and 25℃, respectively. The sporophytes were able to uptake NO3--N and NH＋-N when the concentration of nitrogen was lower than 3 000μg·L^-1 , presenting a strategy of open absorption mode. The sporophytes were able to uptake PO43--p when the concentration of phosphate was lower than 30μg·L^-1 , presenting a strategy of saturated absorption mode. Growth performance of the sporophytes was sig- nificantly different at different temperatures. At temperatures ranging from 10 to 30℃, the specific growth rate （SGR） for nutrient-enriched and nutrient-removed treatments showed a trend of decrease after a first increase, reaching the maximum, 19.58%·d^-1 and 19.58%·d^-1, respectively, at 25℃. With the increase of temperature, the content of chlorophyll a and c decreased firstly, and then increased. Growth of these sporophytes was significantly different at different nutrient concentrations. The SGR and the content of chlorophyll a and c for nutrient-enriched treatments were significantly higher than those for nutrient-removed treatments at temperatures ranging from 15 to 25 ℃, from 15 to 30 ℃ and from 20 to 30 ℃, respectively.