Production of Chimeral Thalli by Protoplast Fusion in Porphyra yezoensis and P.tenera

细胞融合是提高植物品质的优越技术。本研究试图通过细胞融合的方法，从红藻紫菜中产生嵌合体。为了进行细胞融合，需要产生大量的原生质体。我们从自然生境中寻找能够降解藻类细胞壁的细菌，分离出3株能产生大量细胞壁降解酶(-1，4-甘露聚糖酶、-1，3-木聚糖酶和卟啉酶)的细菌。自发性突变体的绿色叶状体也是从野生株中获得的。从野生型的菌体中提取了一些原生质体。经-1，4-甘露聚糖酶、-1，3-木聚糖酶和卟啉酶处理，获得绿色突变体。将这些原生质体暴露在聚乙二醇(PEG)中，诱导它们融合。经聚乙二醇化处理的原生质体发育成形状不规则的愈伤组织，并在愈伤组织中形成大量的植株。这些植株长成了分区杂色的嵌合体(嵌合体-I)，除了棕色或绿色的叶状体外，还有棕色和绿色的部分组成。显微镜下可见嵌合体-I的绿色区段变为棕色成熟细胞。一些单孢子从嵌合体中释放出来，发育成由棕色和绿色组成的嵌合体，另一些则是棕色或绿色的嵌合体。嵌合体由嵌合体I的单孢子发育而成，释放出果梗孢子。这些果肉孢子长成丝状体并产生壳孢子。38.4%的海螺孢子长成棕色和绿色的嵌合体。因此，Chimera-I可能是由条斑侧耳和侧耳侧耳融合细胞发育而来的菌体。

Cell fusion is the superior technique to improve the quality of plants. In this study was tried to produce chimeral thallus from a red sea algae, Porphyra, by cell fusion. For carrying out cell fusion it is necessary to produce a number of protoplasts. We searched bacteria capable of degrading the cell wall of algae from natural habitats, and isolated 3 strains of bacteria which could produce a lot of cell wall-degrading enzymes ( -1,4-mannanase, -1,3-xylanase, and porphyranase). A green thallus of the spontaneous mutant was also obtained from the wild type of P.tenera. A number of protoplasts from thalli of the wild type of . Yezoensis and the green type mutant of P.tenera by the treatment with -1,4-mannanase, -1,3-xylanase, and porphyranase. These protoplasts were induced to fuse by exposing them to polyethylene glycol (PEG). The PEG-treated protoplasts developed into calli of irregular shapes, and a large nummber of plantlets were formed from the calli. These plantlets grew into sectorially variegated chimeral thalli (chimera-I) composed of brown and green sectors, in addition to brown or green thalli. Microscopical observation revealed that green sector of chimera-I turned into brown mature cells. Some monospores released from chimera-I grew into chimeral thalli composed of brown and green, and others bedame brown or green thalli. A chimeral thallus developed from monospores of chimera-I released carpospores. These carpospores grew into conchocelis and produced conchospores. A 38.4 % of the conchospores grew into chimeral thalli composed of brown and green. Therefore, chimera-I was supposed to be a thallus developed from fusion cell of P.yezoensis and P.tenera.