光照和盐度对江蓠在N、P持续加富条件下生长和吸收的影响

The effects of light and salinity on Gracilaria growth and salt absorption in continual enrichment of nitrogen and phosphorus

为研究菊花江蓠和细基江蓠繁枝变型在N、P持续加富营养盐条件下生长和吸收的特征及主要环境因子条件,模拟实际生产情况,采用不同光照和盐度进行单因子实验,通过相关分析、单因素分析和多重比较检验。结果显示,在高浓度N、P条件下菊花江蓠和细基江蓠繁枝变型生长率在光照60~100μmol·m^-2·s^-1时相对较高;菊花江蓠在盐度15~27范围内生长率差异不显著(p>0.05),细基江蓠繁枝变型在盐度15、20生长率显著高于盐度为27时的生长率(p<0.05)。菊花江蓠无机氮(IN)吸收速率在光照20~100μmol·m^-2·s^-1时无显著变化,但显著高于140μmol·m^-2·s^-1时的吸收速率(p<0.05),细基江蓠繁枝变型无机氮吸收速率在光照60~140μmol·m^-2·s^-1时相对较高,2种江蓠无机磷(IP)吸收速率在光照60~100μmol·m^-2·s^-1时高;菊花江蓠在盐度15~27范围内无机氮吸收速率无显著差异(p>0.05),在盐度20~27范围内无机磷吸收速率显著高于盐度15(p<0.05),细基江蓠繁枝变型无机氮、无机磷吸收速率在盐度15~20时显著高于盐度27(p<0.05)。2种江蓠相对生长率和N、P吸收速率在适宜光照和盐度条件下10 d时最高,10 d后逐渐下降;细基江蓠在盐度27条件下10 d时无机氮吸收受抑制,在光照20μmol·m^-2·s^-1和140μmol·m^-2·s^-1条件下10 d时无机磷吸收受抑制。2种江蓠在适宜光照强度下,营养盐吸收速率与相对生长率呈显著正相关。光照对2种江蓠生长和营养盐的吸收影响大于盐度,细基江蓠对光照和盐度敏感,适宜范围窄于菊花江蓠。

For exploring environmental conditions and the features of Gracilaria lichevoides and Gracilaria tenuistipitatavar.liui growth andsalt absorptionin continual enrichment of nitrogen and phosphorus,a series of single factor experiment was proceeded to obtain the optimum growth andsalt absorbing conditions under different conditions of light or salinity,through correlation analysis,single factor analysis and multiple comparison.The results showed that the growth rates of G.lichevoides and G.tenuistipitatavar.liui in 60μmol·m^-2·s^-1~100μmol·m^-2·s^-1 were higher than the other groups(p<0.05),and the growth rates of G.tenuistipitatavar.liui in salinity(15,20)were higher than in salinity 27(p<0.05),but there was no significant difference for G.lichevoides in salinity(15,20,27).For G.lichevoides,the absorbing rates of inorganic nitrogen for in 20μmol·m^-2·s^-1~100μmol·m^-2·s^-1 were higher than in 140μmol·m^-2·s^-1(p<0.05),and the absorbing rates of inorganic phosphorus in 60μmol·m^-2·s^-1~100μmol·m^-2·s^-1 were higher than the other lighting conditions(p<0.05);the absorbing rates of inorganic nitrogen in salinity range(15~27)had little difference,but the absorbing rates of inorganic phosphorus in salinity 20,27 were higher than those in 15(p<0.05).For G.tenuistipitata var.liui,the absorbing rates of inorganic nitrogen in 60μmol·m^-2·s^-1~140μmol·m^-2·s^-1 were higher than those in 20μmol/m2/s,and the absorbing rates of inorganic phosphorus in 60μmol·m^-2·s^-1~100μmol·m^-2·s^-1 were higher than in the other light conditions(p<0.05);the absorbing rates of inorganic nitrogen and inorganic phosphorus in salinity 15~20 were higher than those in salinity 27(p<0.05).The relative growth rates and the absorbing rates of inorganic nitrogen and phosphorus for the two kinds of gracilaria under the optimum condition reached the top on the tenth day and declined later.For G.tenuistipitata var.liui,the absorbing of inorganic nitrogen in salinity 27 and the absorbing of inorganic phosphorus in 20μmol·m^-2·s^-1 and 140μmol·m^-2·s^-1were suppressed on the tenth day.There was positive correlation between nutritive salt absorbing rate and relative growth rate under proper light intensity for the two kinds of gracilaria,and the influence of light on their growth and nutritive salt absorbing was bigger than that of salinity.In addition,G.tenuistipitata var.liui was sensitive to light and salinity,which suggested that its appropriate range was narrower than G.rialichevoides.