Cytogenetic studies on some members of tribes Hesperidae, Mathioleae, Sisymbrieae of Brassicaceae of Kashmir.

It studied in detail morphological and cytogenetical analysis of 21 species belonging to 3 tribes namely Methioleae, Hesperideae and Sisymbrieae of Brassicaceae. Chromosome numbers in the texa were investigated from range 2n=10(Arabidopsis thaliana) to 42 (sisymbrium brassici form). Cytological details of 5 species namely Arabidopsis striceta (n=8), Matthiola flavida (n=6), Erysimum altacium (n=17), chorispora sabulosa (n=7) and Tetracme Pamirica (n=14) were studied for the first time. 16 species were also studied from Somatic chromosomes

Synthesis and properties of some cyclic AMP alkyl phosphotriesters

Cyclic AMP was converted to its phosphotriesters according to the classical approach of phosphate activation with a sulfonyl chloride, followed by esterification with an alcohol. The methyl, ethyl, propyl, butyl and cetyl triesters were prepared, and some of their physical-chemical properties determined. Alkaline hydrolysis of these alkyl phosphotriesters resulted predominantly in ring opening. On the other hand, nucleophilic attack by thiourea led to the formation of cAMP as the main product. The conclusion can be drawn from these results that cAMP phosphotriesters could serve as suitable storage forms of cAMP, and cyclic triesters may be the best vehicle of transporting nucleotides through biological membranes

Cytogenetic studies of some species of Astragalus L. of Kashmir.

The work studied 24 species of Astragalus collected from places ranging in altitude from 1500m-4100m. Seventeen (17) species were collected from Ladakh. The chromosome counts for x=17 species is made for the first time.23 species in the present collection are diploid and only one is tetraploid. The study reveals that out of 23 diploid species, 22 have X=8 and 1(A.melanostachys) has X=6. The tetraploid species belongs to the series with X=8. Somatic chromosomes of 20 diploid species of this genus were also studied. Somatic chromosomes of A.grahamianus, A.leucoceplalus and A.zanskarensis are investigated from two populations each

Cytogenetic studies of some Indian alliums.

The work studied 16 species which includes 5 cultivated species and 11 wild species. These species were collected in 21 cytotypes of which 54.5% are polyploid and 45.4% diploid. The species investigated the species having chromosome numbers in multiple of the base number 8 and not having any terminal chromosomes, except for A.consanguinem. The other species have two or more nucleolar chromosomes. Meiosis in all the diploid species follows a normal course.. The study reveals that majority of the polyploid species of Allium are segmental alloploids and show highly erratic meiosis which is characterized by multivalent formation and irregular segregation of chromosomes at anaphase. The intergenomic pairing, crossing over and irregular anaphatic distribution lead to the formation of pollen grains carrying numerically and/or structurally altered karyotypes. It also finds that Chromosome interchanges are infrequent in the genus Allium. Among the polyploidy species meiosis proceeds normally only in tetraploid, A.ampelosprasum and A.thomsoni