Volume 84, Issue 6
December 1976, pages 201-237
pp 201-209 December 1976
The embryo enters the uterus at the morula stage of development. The progestational response of the uterus is characterized by the enlargement of the uterine lumen near the centre of the right uterine cornu into a large spherical chamber in which the blastocyst undergoes nidation, and by a pronounced hypertrophy of the uterine glands on all the sides of the implantation chamber. The implantation of the blastocyst is circumferential, and the embryonic disc is directed towards the side of the uterus which is between the mesometrial and the lateral sides. The primitive amniotic cavity is formed by cavitation and the definitive amnion is later formed by the formation of folds from the margin of the embryonic disc.
pp 210-214 December 1976
Three species ofHelvella are recorded from India for the first time. These areH. fusca, H. macropus andH. solitaria. Brief descriptions are given.
pp 215-225 December 1976
The occurrence and nature of cross-protection in the ‘blast’ disease ofPanicum repens L. were studied using detached leaves of the host, two incompatible (P1,M1) isolates and a compatible (PR) isolate. Protection was evident when leaf tissues were inoculated with a mixture ofP1 andPR conidia but not with a mixture ofM1 andPR conidia. However, prior inoculation of the leaves with eitherP1 orM1 protected the leaves against blast caused by the compatiblePR isolate but the protection was highly localized. The nature of protection is discussed in terms of competition between the isolates for infection sites and interactions between the host and the preinoculant.
pp 226-230 December 1976
The present studies indicate that the differentiation of ecotypes inEuphorbia hirta into erect and prostrate forms as related to soil moisture and compaction is not complete and often they may be merely plastic modifications. Besides, the reproductive strategies of the two ecotypes and different in that the prostrate form has greater reproductive effort compared to vegetative growth. It was also shown that the two populations show differences in their abundance at different seasons of the year.
pp 231-237 December 1976
The exomorphic structures of the seeds ofSwertia has been examined and a key to the commonly occurring Himalayan species is presented. Informations on count, size, shape, colour and surface features of the seeds are given for 31 species. A representative figure of each seed type is illustrated.