Abstract

Pollen morphology of Mesembryanthemum criniflorum L.f. in the plants treated or not treated with gamma irradiation of 5, 10, 20, 30, 40 and 50 Krad dosages have been studied using LM and SEM. Pollen grains in the control plants are basically 3(-4)-colpate-colporoidate. Besides, parasyncolpate grains occur as a variation. The pollen size is variable having a wide range(P x E: 17-37 x 14-35μm). The pollen sculpture is spinulose-punctate.In the irradiated plants, the pollen size range drastically narrowed down.While the pollen grains of the plants treated with 5, 20, 30, 40 and 50 Krad dosages had the same pollen morphology as in the controls, the plants treated with 10 Krad dosage showed a complete change in the exine ornamentation exhibiting 'Microoverrucate' pattern as against the spinulose pattern, characteristic of the species. Since the apertural character did not deviate from the basic 3-colpate-colporoidate condition, it has been contended that the exine surface pattern and the apertural features may be considered as separate characters controlled by different genes, and that the change in the exine pattern may be attributed to the mutation of the gene/genes controlling he pattern.

中文摘要

使用光學顯微鏡與電子顯微鏡來研究龍鬚海棠，經過伽碼輻射以5, 10, 20, 30, 40, 50Krad等不同分量處理後之花粉形態變化。基本上，花粉粒為3(-4)溝粒到3(-4)類溝粒，其花粉粒大小為13-37 x 17-35μm(PxE)，花粉紋路為細尖。經由輻射處理之植物，其花粉粒大小均會產生劇烈之遞減；而經過伽碼輻射以5, 20, 30, 40, 50Krad等不同份量處理後，花粉形態與未經處理者相同，但以10Krad份量處理者，則可見其花粉紋路完全變化，由細尖到細半圓型。故由此二種處理可看出花粉口，花粉紋路之變化可能受不同基因所控制。而由花粉壁紋之變異型也可能提供作為調控基因與基因變異之機制。

Keyword: Pollen grains, Gamma irradiation, Mesembryanthemum