缺氮和高光对集球藻光合生理与油脂积累的影响

Nitrogen deficiency and highlight affect photophysiology and lipid accumulation of Palmellococcus miniatus

微藻是生产生物柴油理想的生物资源,对产油微藻的生理生化特性的研究具有重要意义。本文以一种耐碱性产油微藻集球藻为研究对象,将其置于两种光强水平(100和600μmol photons·m^(-2)·s^(-1))下培养,探讨缺氮对集球藻光合生理及油脂积累的影响。结果表明:缺氮培养下,集球藻光系统II的最大光化学效率F_v/F_m下降,电子从QA-到QB的电子传递受阻,光合作用受到抑制,生长表现缓慢,蛋白质含量降低,而油脂含量增加;在高光的耦合作用下,其光合作用进一步受到抑制,蛋白质含量下降,但油脂含量与低光缺氮条件下相比,没有显著变化。研究表明,缺氮使集球藻碳同化进入油脂合成代谢,增加其油脂含量,而光强对油脂积累的诱导效应不明显。

Microalgae is an ideal biological resource to produce biodiesel. It is important to study the physiological and biochemical characteristics of lipid-rich microalgae. In this study,Palmellococcus miniatus,a kind of alkali-resistant green microalgae,was cultured under low（ 100 μmol photons·m-2·s-1） and high（ 600 μmol photons·m-2·s-1） light,and the effects of nitrogen deficiency on photophysiology and lipid accumulation of P. miniatus were investigated. The results showed that nitrogen deficiency decreased the photosystem II maximum photochemical yield（ Fv/ Fm）,inhibited the electron transfer from QA-to QB,and lowered the protein content. The inhibition of photosynthesis resulted in the reduction of the growth and biomass. However,nitrogen deficiency induced significant accumulation of lipid. When supplemented with high light,the photosynthesis of P. miniatus was further suppressed and the protein content was decreased to a great extent. In contrast,the lipid content did not show significant change as compared with that under the low light and nitrogen-deficient condition. Our results indicated that lipid accumulation was stimulated by nitrogen deficiency,while light intensity showed little effect on it.