坛紫菜天然红色变异体的分离与特性分析

Isolation and characterization of a red type variant in Porphyra haitanensis Chang et Zheng(Bangials,Rhodophyta)

在坛紫菜栽培群体中发现一棵红色块与野生色块相嵌的颜色变异叶状体,在实验室进行红色藻块的体细胞再生克隆培养,获得了纯红色变异体。与野生型相比,红色变异体在叶状体的形态、颜色、生长速度、成熟、藻胆蛋白及叶绿素含量等方面均存在着明显的差异。红色变异体的颜色呈铁锈红色,体形宽大,生长速度明显快于野生型,培养400多天仍不成熟。与野生型相比,它的叶状体活体吸收光谱除各吸收峰的峰值有变化外,第4个吸收峰的峰顶(藻蓝蛋白的吸收峰)向短波方向移动了约3 nm,表明其藻红蛋白的结构有可能发生了改变。另外,它的藻红蛋白(PE)和叶绿素a的含量均显著增加,但藻蓝蛋白(PC)的含量有所下降,使得PE/Chl.a和PC/Chl.a的比值较高,但PE/PC比值较低。培养400d的红色变异体的体细胞再生体中,正常叶状体和畸形叶状体的百分数分别为78.49%和19.81%,根丝细胞苗占1.7%,未见细胞团出现,说明该变异体的不成熟是由叶状体的细胞分化严重延缓所致。

A sectored blade of Porphyra haitanensis with a wild sector and a red sector was found in the cultivating population.The pure red type of variant blades were regenerated from the somatic cells of the red sector.Some obvious differences have been found between the blades of the red variant and the wild type,in morphology,color,growth rate,maturity time,and contents of chlorophyll a（Chl.a） and phycobilioprotein（PE,PC）.Compared with the wide type,the blade of the red type variant was wider,showing reddish brown color,grew faster,matured far later and did not mature even being cultured more than 400 days.In vivo absorption spectrum of its blades showed that,the absorption peak of phycocyanin（PC） shifted about 3 nm to short-wave,indicating that the structure of the phycocyanin may have changed.In addition,the contents of chlorophyll a and phycoerythrin（PE） of this variant significantly increased,but the phycocyanin content decreased,showing a higher ratios of PE / Chl.a and PC / Chl.a,lower ratio of PE / PC.When the single somatic cells were enzymatically isolated from the 400-d-old blade of this red variant which was still immature,and regenerated into only three types of blades： normal blades（about 78.49%） and abnormal blades（19.81%） and the rhizoid blades（1.7%） without appearance of any cell-masses.This result indicated that the serious delaying of cell differentiation of the variant blade probably led to its immuturity.