盐度对六株硅藻生长及脂肪酸组成的影响

在温度为22±1℃,盐度为18‰、28‰和38‰的条件下,用F/2培养基对青岛海洋大学微藻种质库保存的6株硅藻(纤细角毛藻Chaetoceros gracilis B13; 筒柱藻Cylindrotheca fusiformis B211;三角褐指藻 Phaeodactylum tricomutum B114, B118,B221;新月菱形藻 Nitzschia closterium B222) 进行培养,在指数生长期末期进行收获,测定了6株硅藻的生长及脂肪酸组成.实验结果表明: 盐度对六株硅藻的生长及脂肪酸组成均有影响,但作用结果因种而异.B13的相对生长率随着盐度的增加而增加;B114和B222的相对生长率随着盐度的增加而降低.B13的干重随着盐度的增加而增加,在盐度为38‰时达到最大值(0.21);B118、B114、B221 和B222的干重均在盐度为28‰时达到最大值;盐度对B211的干重影响不明显(0.35～0.36).六株硅藻的主要脂肪酸为16:0、16:1(n-7)和20:5(n-3),B211还含有较多的20:4n-6(5.6～7.4‰),B13含有较多的14:0 (20.O～30.9%).B211、B221和B222的饱和脂肪酸总合随着盐度的增加而降低,在盐度为18‰时达到最大值(占总脂肪酸的百分比分别为41.7%、37.6%和31.7%).而B13、B118和B114的饱和脂肪酸总合在盐度为28‰时含量最高(分别为48.1%、31.0%和33.0%).B118、B114、B221和B222的单不饱和脂肪酸总合随着盐度的增加而增加,而B13和B211单不饱和脂肪酸总合随着盐度的增加而降低.B13、B118、B114和B222的多不饱和脂肪酸总合在18‰时含量最高(分别为31.3%、23.4%、19.6%和18.6%).B211和B221的多不饱和脂肪酸总合在28‰时含量最高(分别为25.1%和16.3%).

EFFECTS OF SALINITY ON THE GROWTH AND FATTY ACID COMPOSITION OF SIX STRAINS OF MARINE DIATOMS

The effect of salinity (18‰,28‰ and 38‰) on the growth and fatty acid composition of six strains of marine diatoms Chaetoceros gracilis(B13),Cylindrotheca fusiformis (B211),Phaeodactylum tricornutum(B114,B118 and B221) and Nitzschia closterium (B222) was investigated.The relative growth rate showed an increase in B13 and a decrease in B114 and B222 with the increase of salinity.The dry weight of B13 increased with the increase of salinity and reached its highest value(0.21)at the highest salinity(38‰).The dry weight of B114,B118,B221 and B222 both reached their highest values(0.26,0.32,0.40 and 0.30,respectively) at salinity 28‰.No significant difference Was observed in B211 (O.35～0.36).The major fatty acids of the 6 strains were 16:0, 16:1(n-7) and 20:5(n-3).B211 also had a high percentage of 20:4n-6 (5.6～7.4%).B13 also had a high percentage of 14:0(20.0～30.9%).Saturated fatty acids decreased with the increase of salinity in B211,B221 and B222,and reached their higllest values in 18‰ in B211(41.7%),B221(37.6%) and B222(31.7%),and in 28‰ in B13(48.1%),B114 (33.0%)and B118 (31.0%).Monounsaturated fatty acids increased in B114,B118,B221 and B222 while decreased in B13 and B211 with the increase of salinity.Polyunsaturated fatty acids had their highest values in 18‰ in B13(31.3%),B114 (19.6%),B118(23.4%) and B222(18.6%),and in 28‰ in B211(25.1%)and B221(16.3%).