关键词：
Pyropia chauhanii;60Co-γ射线;优良品系;叶状体;壳孢子;耐高温
摘 要：
为培育出藻体薄且适合在我国南方高水温海区栽培的紫菜新品种,利用~(60)Co-γ射线辐照和高温胁迫处理印度产紫菜Pyropia chauhanii野生型品系(PC-WT)的叶状体,分离出优良品系PC-M,随后通过研究2个品系在耐高温性、生长、主要光合色素含量、单孢子和壳孢子放散量等方面的差异后发现,在18和23°C温度组中,2个品系的壳孢子存活率、分裂率和假根发生率均无显著性差异,但在27和29°C温度组中,PC-M品系的壳孢子存活率比PC-WT品系分别提高了250.7%和305.4%,分裂率分别提高了42.4%和67.1%,假根发生率分别提高了86.6%和175.3%;将在23°C下培养30 d的叶状体分别置于18、23、27和29°C下培养10 d,在18、23和27°C组中,PC-M品系的叶状体绝对生长率分别是PC-WT品系的5.1、5.3和7.5倍,特定生长率分别是PC-WT品系的1.3、1.3和1.8倍;在27°C下培养15 d或在29°C下培养10 d,PC-WT品系的叶状体均放散了大量的单孢子,藻体流失严重,仅剩下基部,而PC-M品系的叶状体均没有放散单孢子、藻体形态完整、光泽好、生长速率快,培养至30 d后才发生轻微的卷曲。与PC-WT品系相比,常温组(23°C)的PC-M品系的3种主要光合色素(chl.a、藻红蛋白和藻蓝蛋白)含量以及壳孢子放散量分别提高了39.4%、209.8%、94.8%和36.7%,但藻体的平均厚度反而减少了31.6%。上述结果证实,与PC-WT品系相比,PC-M品系具有藻体薄、色素含量高、生长快、耐高温、壳孢子放散量大、单孢子不放散等优点,有望被培育成适宜栽培的新品种。
译 名：
Selection and characterization of an improved strain of Pyropia chauhanii(Bangiales, Rhodophyta)
作 者：
CHEN Shasha;DING Hongchang;YAN Xinghong;College of Fisheries and Life Sciences, Shanghai Ocean University;Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources,Shanghai Ocean University, Ministry of Education;
关键词：
Pyropia chauhanii;;60Co-γ ray;;improved strain;;gametophytic blades;;conchospores;;high-temperature resistance
摘 要：
In order to develop a new variety of Pyropia with thin blade, which is suitable for cultivation in the aquaculture areas with high temperature along the coast of South China, the blades of the wild-type strain(PC-WT)of Pyropia chauhanii were irradiated with ~(60)Co-γ rays and cultured at a high temperature(30 °C) for 25 days, and then the improved strain of PC-M was obtained. Subsequently, PC-M was compared with PC-WT for hightemperature resistance, growth, contents of major photosynthetic pigments, the releasing ability of monospores and conchospores. The results showed that the rates of survival, division and rhizoid germination of conchospores were not significantly different between PC-M and PC-WT at 18 and 23 °C, but the survival rates were 250.7% and305.4% higher, the division rates were 42.4% and 67.1% higher, the rhizoid germination rates were 86.6% and175.3% higher in the former than those in the latter at 27 and 29 °C, respectively. The F1 gametophytic blades of PC-M and PC-WT were cultured at 23 °C for 30 days and then cultured at 18, 23, 27 and 29 °C for another 10 days, in the group of 18, 23 and 27 °C, the absolute growth rates of PC-M blades were 5.1, 5.3 and 7.5 times those of PC-WT, and the specific growth rates were 1.3, 1.3 and 1.8 times those of PC-WT, respectively. The apical and middle parts of PC-WT blades were disintegrated because of releasing a large number of monospores after being cultured for 15 days at 27 °C and 10 days at 29 °C, and only the basal parts of the blades remained intact. On the other hand, PC-M blades grew rapidly with normal color and shape without releasing monospores, just slightly curled after being cultured for 30 days. In addition, the contents of three major photosynthetic pigments(chl. a, PE and PC) and the conchospore numbers in PC-M at a suitable temperature(23 °C) were 39.4%, 209.8%, 94.8% and36.7% higher than those of PC-WT, respectively. Meanwhile, the thickness of blades of PC-M was 31.6% thinner than that of PC-WT. The above results indicated that PC-M has thinner blade, higher contents of the major photosynthetic pigments, faster growth speed, higher-temperature resistance, larger number of conchospore release and no monospore release as compared with PC-WT. It is therefore potential to be developed into a new variety suitable for cultivation along the coast of South China.
