N、P营养盐胁迫对两株布朗葡萄藻生长的影响

采用批次培养方法,在光照强度60、110μmol/m2·s下分别设置了7个不同的氮、磷浓度(N:0—3500μg/L,P:15—775μg/L),研究两株布朗葡萄藻(Botryococcus braunii)对氮、磷胁迫的敏感性差异,筛选高营养利用效率的优良藻株。结果表明:两株藻对氮磷营养胁迫的耐受性存在差异,B.braunii764株对氮胁迫具有较高耐受性,而B.braunii765株对磷胁迫具有较高耐受性。光照强度110μmol/m2·s,不同氮浓度下B.braunii764株其平均生长速率均显著高于其他各处理组;不同磷浓度下B.braunii765株其平均生长速率显著高于B.braunii764株。在试验设定的光照强度条件下,适当增加光照强度能够显著降低氮胁迫对布朗葡萄藻生长的抑制效应。在光照强度110μmol/m2·s下,氮浓度3500μg/L时两株布朗葡萄藻平均生长速率与在正常Chu-10培养基条件下无显著差异。磷浓度775μg/L时两株布朗葡萄藻的平均生长速率均显著低于正常Chu-10培养基条件,增加光照强度对磷胁迫下藻细胞的生长无显著作用。两株布朗葡萄藻在第2天时磷吸收与初始磷浓度呈正相关关系,氮吸收在3500μg/L时出现饱和现象。布朗葡萄藻的生长更容易受到培养基中磷营养胁迫的影响。

EFFECTS OF NITROGEN AND PHOSPHORUS STRESS ON THE GROWTH OF BOTRYOCOCCUS BRAUNII

The growth of two Botryococcus braunii strains were studied under seven nitrogen and phosphorus stress levels (N: 0-3500/μg/L, P: 15-775μg/L) in batch culture at two light intensities of 60 and 110 μmol/m~2.s. Results showed that the tolerance of B. braunii to N and P stress was different between strains, which was further affected by light intensity. B. braunii 764 grew better under N stress, while B. braunii 765 grew better under P stress. The average growth rates of B. braunii 764 with all N stress treatments were significantly higher at the light intensity of 110 μmol/m~2.s than any other treatments. There was no significant difference among the average growth rates of B. braunii 764 and 765 at 60 μmol/m~2.s and B. braunii 765 at 110 μmol/m~2.s treated with N stress. The average growth rates of B. braunii 764 at 110 μmol/m~2.s were significantly lower than other P stress treatments. There was no significant difference among the average growth rate S or B. braunii 764 and 765 at 60μmol/m~2.s and B. braunii 765 at 110 μmol/m~2.s treated with P stress. Inhibitory effect of N stress on the growth of B. braunii strains was alleviated by the increase of light in-tensity from 60 to 110/μmol/m~2.s. The growth rates of two B. braunii strains under 3500 μg/L N treatment showed no notable difference compared with that under normal Chu-10 medium. The uptake rates of N and P exhibited linear de-pendence with the initial levels at the 2~(nd) day. N uptake rate reached a saturation point at 3500 μg/L N at the 2~(nd) day.