坛紫菜人工色素突变体的诱变与分离

Induction and isolation of artificial pigmentation mutants in Porphyra haitanensis Chang et Zheng (Bangiales, Rhodophyta)

坛紫菜叶状体经一定剂量的60Co-γ射线辐射再培养一段时间后,出现了少量色素体颜色发生变异的细胞,它们呈点状无规则地镶嵌在野生型细胞中。培养3周后,色素变异细胞分裂并形成了不同颜色的细胞块, 其颜色呈桔红、桔黄、浅黄褐、浅红、紫红、紫褐、黄绿、绿色等。在辐射剂量0-1 100 Gy范围内,叶状体上色素变异细胞块的出现频率随着辐射剂量的增加而增加;但辐射剂量增至1400 Gy时,色素变异细胞块出现的频率反而下降,说明1 100 Gy是合适的辐射剂量。在同一个叶状体的不同部位上色素变异细胞块出现的频率是不同的,从基部到稍部,随着部位的上移而逐渐增加。用酶解法把含色素变异细胞的叶状体细胞单个分离出来并进行离体培养,在它们的再生体中,出现了多种单色的色素突变叶状体,从中分离到tan(红褐色)、bor(深结红色)、ceb(紫红色)、hon(枯草色)、cac(深黄绿色)等不同颜色的纯色突变体。从各单色突变体中分离出来的丝状体,其颜色与各自的叶状体相同。各突变体的丝状体成熟后,放散的壳孢子长成单色的F1叶状体,其颜色与各自最初的母体叶状体相同,说明所得到的上述突变体是稳定的色素突变体。

The young gametophytic blades of Porphyra haitanensis Chang et Zheng, developed from the conchospores of the wild type, were treated with 60Co-γ ray to induce mutations. Color-mutated cells showing purplish red, pink, red orange, orange, yellow green, green and other mutated colors appeared in the treated blades after culture for 1 week. After culture of 3 weeks, the color-mutated cells grew to be cell-clusters with different colors. When the irradiation dose increased from 0 Gy to 1100 Gy, the frequency of the color-mutated cell-clusters was higher with increase of the dose. However, further increase of the dose up to 1400 Gy, decreased the frequency of the color-mutated cell-clusters. These results indicated that 1100 Gy is the suitable dose for inducing mutations of P. haitanensis blades. The frequency of the color-mutated cell-clusters was different in the different parts of a blade, increasing from the base to the tip of the blade. Single cells were isolated enzymatically from the color-mutated blades, and regenerated into blades among where appeared some single-colored mutant blades and a few spottedly variegated blades consisting color-mutated cells and the wild-type cells. Five pigmentation mutant strains (conchocelis) with colors of red brown, dark orange, pink, golden brown and dull yellow green were established from the single-colored mutant blades by parthenogenesis. They were named as tan, bor,ceb, hon and cac, respectively. Their colors were relatively stable in both gametophytic blade and conchocelis phases. The F1 gametophytic blades of each mutant strains, showed the same color with its mother blades, respectively.