利用液相氧电极技术研究“海天1号”海带(Saccharina japonica)幼孢子体光合及呼吸速率

Preliminary Studies on the Photosynthetic and Respiration Rate of Young Sporophyte of a New Saccharina Variety “Haitian No. 1” Using Liquid-Phase Oxygen Measurement System

关键词:  “海天1号”海带  幼孢子体  环境因子  相对生长速率  光合作用

Key words:  Saccharina japonica “Haitian No. 1”  Young sporophyte  Environmental factors  Relative growth rate  Photosynthetic rate

摘要:

“海天1号”海带是南方耐高温品种与北方高产品种杂交后，经过几代选育获得的海带新品系，具有产量高、耐高温、成熟稍早等特点(暂命名为“海天1号”海带)。为探究“海天1号”海带幼孢子体在不同环境因子下的生理适应性，设置了温度、光强及营养盐3个单因素实验，利用液相氧电极技术研究其对“海天1号”海带幼孢子体(1–2 cm)表观光合速率(Pn)和呼吸耗氧速率(R)的影响，并测定相对生长速率(Relative growth rate, RGR)。结果显示：(1) 温度为14℃、光强为80 μmol photons/(m2·s)、氮营养盐为6 mg/L(N/P=10∶1，下同)环境下，幼孢子体的RGR和Pn均较大。在温度为22℃、光强为100 μmol photons/(m2·s)、氮营养盐浓度为10 mg/L条件下，R最强。(2) 22℃组的幼孢子体生长受到抑制，其RGR显著低于14℃组(P<0.05)。20 μmol photons/(m2·s)与80 μmol photons/(m2·s)光强组的RGR存在显著性差异(P<0.05)。单因素方差分析显示，5个营养盐浓度组之间幼孢子体的RGR无显著性差异(P>0.05)。(3) 随着温度、光强、营养盐浓度增加，幼孢子体的Pn呈先上升后下降的趋势，14℃组Pn显著高于其他温度组，氮营养盐浓度4 mg/L和6 mg/L组的Pn显著高于2、8和10 mg/L组(P<0.05)。在本实验条件下，R和Pn呈负相关。(4) 光强对幼孢子体P/R (总光合速率/呼吸耗氧速率)的影响较小，温度和营养盐浓度对其影响较大。正交实验结果显示，适宜“海天1号”海带幼孢子体培养的条件为光强50 μmol photons/(m2·s)、温度16℃、氮营养盐浓度5 mg/L。

Abstract:

Here we applied liquid-phase oxygen measurement system with single factor test to explore the physiological adaption of young sporophytes (1–2 cm) of a new Saccharina variety “Haitian No. 1” to different environmental factors, especially the effects of temperature, light intensity and nutritive salts on their growth rate (RGR), apparent photosynthetic rate (Pn), and respiratory oxygen consumption rate (R). RGR was specifically tested in an orthogonal experiment. The new Saccharina variety, temporarily named as “Haitian No. 1”, was bred through targeted selection in several years. One of the parents was markedly tolerant to high temperatures and the other possessed a great individual weight. The results showed that the values of RGR and Pn were the highest when the temperature was 14℃, the light intensity was 80 μmol photons/(m2·s), and the nitrogen concentration was 6 mg/L (N:P = 10:1, the same below). The highest R appeared at 22℃, 100 μmol photons/(m2·s), and 10 mg/L nitrogen. The growth of sporophytes was inhibited at 22℃, and RGR was significantly lower than that at 14℃ (P<0.05). RGR at 20 μmol photons/(m2·s) was significantly lower than that at 80 μmol photons/(m2·s) (P<0.05). As the temperature, light intensity and nutritive salts increased, Pn was initially increased and then decreased. Pn at 14℃ was significantly higher than that of other groups. Pn values at the nitrogen concentration of 4 mg/L and 6 mg/L were significantly higher than those at 2, 8 and 10 mg/L (P<0.05). R was inversely correlated with Pn under the experimental conditions. Temperature and nutritive salts were found to be more impactful than light intensity on P/R (total photosynthetic rate/respiratory oxygen consumption rate). The orthogonal test results suggested that the suitable culture conditions for sporophytes of “Haitian No. 1” were 50 μmol photons/(m2·s) and 5 mg/L nitrogen at 16℃.