Volume 85, Issue 2
February 1977, pages 43-106
pp 43-47 February 1977
The selection coefficient for the deficiency allele and the proportion of the two alleles in the populations are estimated. The apparent vegetative and reproductive vigour in the populations with the factor is attributed to the combined effect of low population density caused by the death of the double recessives and the higher selective value of the heterozygotes in these populations. A model of balanced polymorphism involving a recessive lethal is suggested to explain the results.
pp 48-52 February 1977
Prothalli and juvenile sporophyte of seven species ofDryopteris are described. Spore germination is of Vittaria-type and prothallial development is of the Aspidium-type with the characteristic range of variations in the different species.
pp 53-56 February 1977
A new species,Pillaia khajuriai from the plains of the Assam region, is described based on material collected by the Indo-German Expedition 1957.
pp 57-66 February 1977
The petiolar anatomy of sixteen species belonging to fourteen genera of Bignoniaceae has been studied. Two aspects, namely, the vascular pattern in the slender part of the petiole and the mode of vascular supply from the primary rachis to leaflets or secondary rachii, are taken into consideration. On the basis of the vasculature as seen in transection of the slender part, four main types of petioles have been recognised, while there are three patterns of vascular supply. A key also has been devised to identify these sixteen species.
pp 67-76 February 1977
In an attempt to establish morphologically adjusted relation with rapidly changing environments some of the Bagh ammonoids of Placenticeratid stock have given rise to a variety of heteromorphs, grouped here under a new genusPlacentoscaphites. This group exhibits tendencies (1) to uncoil, retaining the plano-spiral mode of coiling, and (2) to departing from plano-spiral coiling.
In the light of Kauffman’s observations occurrence of these heteromorphs suggests at least three regressive phases in the course of Bagh sedimentation.
pp 77-89 February 1977
Trichomes of 39 species of Trifolieae belonging to six genera have been worked out. On the basis of structure they are classified into nine types and ontogeny of only four types could be studied. The structure and organographic distribution of each type has been described. All types of trichomes have been initiated from single initial cell.
pp 90-99 February 1977
Qualitative and quantitative assessment of the fungal flora of rice field soils yielded 102 species of fungi belonging to 44 genera, when dilution plate, soil plate, root-washing and baiting techniques were employed. The order of efficacy of the methods used was: root-washing > soil plate > dilution plate > baiting.
Baiting method, used specifically to isolate aquatic and keratinophilic fungi from soils was studied in detail with reference to the former. Qualitatively, corn leaf bait was the most efficient one while pine pollens and hemp seeds were least efficient. A semi-quantitative method was employed to study the statistically significant differences among the different factors used. Among the keratinophilic baits,viz., human hair, fowl’s feather and wool, wool bait was least efficient. The results of this investigation are discussed.
pp 100-106 February 1977
200 and 30 potencies of the drugPulsatilla were used and their effect on the ovaries, the uteri and the thyroids of female albino rats were assessed. The higher potency was found significantly to reduce the weight of the uterus as well as the ovary. Drug treated rats exhibited variation in the sequences of vaginal cytology by shortening the proestrus phase of estrus cycle. The drug was found to increase the number of atretic follicles and decrease the number and size of the corpera lutea.Pulsatilla was seen to reduce the height of endometrium as well as those of the luminal epithelium. The two potencies of the drug were found to increase the number as well as the size of the stromal cells. In the drug treated rats the height of epithelial cells of the thyroids were lesser in comparison to the control. In the control group the intrafollicular colloid exhibited vacuoles whereas the intrafollicular colloid in the experimental groups had a homogeneous consistency.