^(60)Co-γ射线辐照对长紫菜的诱变效果及优良品系分离与特性分析

Isolation and characterization of an improved strain of Pyropia dentata(Bangiales,Rhodophyta)after being irradiated by ^(60)Co-γray

长紫菜野生型品系(PD-WT)的叶状体经60Co-γ射线辐照处理后再培养4周,出现了枣红、浅桔红、黄绿、浅桔黄等颜色的色素变异细胞块,其百分率随着辐照剂量的增加而增加;同时,从基部到梢部,其变异率也呈现上升趋势。利用酶解法获得的单个色素变异细胞经离体培养后再生成叶状体,从再生体中筛选出具有明显生长优势的新品系(PD-5)。培养30~70d,PD-5品系的叶状体最大绝对生长率和平均绝对生长率分别为3.76cm/d和2.71cm/d,分别是PD-WT品系的3.60倍和4.22倍。日龄70d时,PD-5品系的叶状体平均体长为117.42cm,是PD-WT品系的4.32倍。日龄45d的叶状体,PD-5品系的叶绿素a和总藻胆蛋白含量分别为8.41mg/g和97.07mg/g,分别比PD-WT品系增加了25.71%和104.44%;PD-5品系的叶状体平均厚度为26.79μm,比PD-WT品系降低了35.04%。PD-5品系的壳孢子放散总量高达421.16万个/贝壳,是PD-WT品系的2.19倍。综上所述,与PD-WT品系相比,PD-5品系在叶状体的生长、3种主要光合色素和色素蛋白含量以及壳孢子放散量等方面,均表现出很明显的优势,有望被培养成可大规模栽培的新品种。

The young gametophytic blades of Pyropia dentata ,developed from conchospores of the wild-type strain （PD-WT ）,were treated with ^60 Co-γray to induce mutation in the experiment.After being cultured for 4 weeks, there were many color-mutated cell clusters showing bright red,red brown,red orange and yellow green in the treated blades.The results showed that the percentage of the colored-mutated cell-clusters increased as increasing of the irradiation dose and from the base to the tip of the blades.Single color-mutated cells were isolated enzymati-cally from the color-mutated blades and were regenerated into blades.An improved strain named as PD-5 strain with the growth advantages was selected from the regenerated blades.In the growth of the blades,the maximum and average absolute growth rates of this improved strain were 3.76 cm/d and 2.71 cm/d,which were 3.60 and 4.22 times that of the PD-WT strain,respectively,during culture from 30 to 70 days.The mean length of F1 ga-metophytic blades of PD-5 strain was 117.42 cm which was 4.32 times that of the PD-WT strain after being cul-tured for 70 days.The contents of Chl a and phycobiliprotein of the PD-5 strain were 8.41 mg/g and 97.07 mg/g,respectively,increasing by 25.71% and 104.44% in contrast with that of the PD-WT ,respectively.The mean thickness of the 45-day-old blades of the PD-5 was 26.79 μm,decreasing by 35.04% in contrast with that of the PD-WT .The total numbers of the conchospores released from the PD-5 strain was 421.16×10^4 per shell,which was 2.19 times that of the PD-WT strain.The aboved results confirmed that the PD-5 strain was characterized by faster growth,higher contents of photosynthetic pigments,larger amount of releasing conchospores than the wild-type strain.Therefore,the improved strain PD-5 had great potential to be applied in commercial cultivation as a new strain.