R. N. Gohil

Studies on male and female meiosis in Indian Allium

Male meiosis in autotetraploid Allium tuberosum (4×=32) is fairly regular, keeping in view its cytological status, with 81 percent of the chromosomes associated in quadrivalents and trivalents. About 5% of the cells have 32 univalents. Anaphase segregation is slightly irregular. While 48% of the pollen mitoses show 16 chromosomes, 87% of the mature pollen is viable as indicated by carmine or iodine staining. — Megaspore mother cells have 64 chromosomes associated in 32 bivalents at metaphase I. Anaphase segregation is normal. In three out of 56 cells studied multivalents, bivalents and univalents are observed as in male meiosis. — It is concluded that the species reproduces by pseudogamous parthenogenesis made possible by meiotic modification. This modification is almost perfect and almost completely specific for female meiosis. Slight effects are observed in male meiosis.

Studies on male and female meiosis in Indian Allium. I. Four diploid species.

Frequency and position of chiasmata at diplotene were studied in pollen mother cells and megaspore mother cells of the same plants of two wild Allium species (A. consanquineum and A. kachrooi) and two cultivated species (a. cepa and A. nigrum), all diploid with 2n=16. Contrary to most reports on sex differences in recombination, chiasma frequencies were higher in male than in female meiosis in all cases. Chiasmata were non-localised except in A. kachrooi megaspore mother cells where they were proximally localised.

Studies on the Cytology of Legumes of Kashmir Himalaya. I. Cytology of Astragalus Melanostachys Benth. Ex Bunge with a New Base Number for the Genus

SUMMARYThe present paper describes, for the first time, detailed cytology of Astragalus melanostachys Benth. ex Bunge with n = 6 and 2n = 12. This is a new and the lowest base number for this genus. Besides describing the cytology of A. melanostachys the validity of other base numbers, reported in this genus, is also discussed.

An Interesting Variation in the Development of the Female Gametophyte of Allium Consanguineum

SUMMARYIn Allium the female gametophyte development is of the bisporic type. In some plants of Allium consanguineum the cell wall is not laid after the first meiotic division in the megaspore mother cell. In such a cell both nuclei lie in the same cytoplasm. After some time one of the nuclei starts dividing and the other degenerates.