Volume 100, Issue 4
August 1990, pages 211-277
pp 211-214 August 1990
Cells and protoplasts ofCatharanthus roseus were immobilized with sodium alginate, agar and agarose. Cells proliferating from the matrix were established separately in liquid suspension and 5 cell lines were isolated which showed differences in their growth and alkaloid synthetic pattern. Cell lines obtained through immobilization of protoplasts yielded higher levels of alkaloids.
pp 215-223 August 1990
The anatomy of stem in 19 species of seedling plams is described in representative species from all the sub-families of Palmae, except Nypoideae and Phytelephantoideae. Morphologically, the stem of juvenile palm is an obconical structure, and that of the adult palms mostly solitary columnar. The cortex of stems in young palms is very wide, and often exceeds the diameter of central cylinder in contrast to very narrow cortex in adult palms. The number of vascular bundles increases several-times from the lower to the upper level of juvenile axis, whereas the number of bundles more or less, remains the same at different levels of the stem in adult palms. There is a wide meristematic zone towards the tip of axis and just below the bases of the young leaves which is responsible for widening of the seedling stem until it attains the mature stem diameter. The xylem of central vascular bundles in young palms is mostly composed of protoxylem elements but, in adult palms, they include well-developed metaxylem vessels. The central ground parenchyma is compact in young palms, spongy and lacunose in adult palms.
pp 225-231 August 1990
The effects of light-dark transition and aplastidic condition by the photobleaching herbicide, 3-amino-1,2,4-triazole, on the activities of enzymes likein vivo nitrate reductase, peroxidase, polyphenol oxidase and catalase were studied in leaves of different ages of 30-day old plants ofVigna unguiculata andZea mays. The activity of nitrate reductase was found to be higher in young leaves and showed a gradual decline at the time of maturity and senescence. In amitrole-bleached young leaves,in vivo nitrate reductase activity was significantly reduced. Although peroxidase is a light-activated enzyme, the enzyme was more active only in fully mature and senescing leaves ofVigna unguiculata. InZea mays, peroxidase activity was more in mature leaves compared to senescent leaves. Interesting feature of this enzyme was that its activity increased upon dark treatment inVigna unguiculata. A similar trend was also observed in polyphenol oxidase activity in mature and senescent leaves ofVigna unguiculata andZea mays. Foliar spray of amitrole increased peroxidase and polyphenol oxidase activities in the young leaves ofZea mays andVigna unquiculata. The results are discussed in relation to age of leaves and the presence or absence of leaf plastids.
pp 233-238 August 1990
Cytomixis with actual transfer of chromatin material has been recorded in 6 woody species, from early prophase to telophase-II. It is more common at early stages of meiosis. Number of pollen mother cells involved vary from 2–8. As a consequence of chromatin migration both hypo and hyperploid meiocytes are seen inSerissa foetida, Symplocos chinensis andQuercus semecarpifolia. However, incordia dichotoma andSalix elegans lower and inCaryopteris odorata higher numbers than the normal complement are not countable due to stickiness or agglutination of chromosomes, respectively. Reduction in pollen fertility in these species is due to the cytomixis. The phenomenon is attributed to certain unknown genetic factors.
pp 239-245 August 1990
Centella asiatica (Linn.) Urb., a clonal perennial herb, grows abundantly on a wide range of habitats in Meghalaya and reproduces both through vegetative and sexual means. The paper presents the competitive interaction between the populations ofCentella asiatica raised from stem cuttings and seedlings, designated as ‘Cc’ and ‘Cs’ respectively. The two categories of plants showed significant differences in growth performance. The numbers of stolons and seeds produced by ‘Cc’ were greater than by ‘Cs’ in both monoculture and mixtures. The total leaf area and dry matter yield of ‘Cc’ were greater in monoculture than in mixtures, while the reverse was true with ‘Cs’. A comparison of the two categories of plants in monoculture and mixtures reveals that with increased proportion (75%) of Cs in mixture, the yield of Cc increased while the yield of Cs decreased in mixed populations having 75% Cc, thus depicting the competitive superiority of Cc over Cs. The relative yield ratio of Cc to Cs which was greater than unity also confirms that population ofCentella asiatica raised from the stem cuttings is more competitive than that developing from the seedings.
pp 247-254 August 1990
Eight species of Lycoperdales have been described. Five of them are recorded here for the first time from India and Himalaya. GenusMorganella is reported for the first time from India.
pp 255-258 August 1990
The alkali maceration technique was used to detect the seedborne nature ofPeronospora parasitica inRaphanus sativus. Four cultivars ‘Japanese white’, ‘Arka nishant’ ‘Pusa desi’ and ‘Pusa reshmi’ were used to confirm the presence of pathogen in the seed. The percentage of embryonal infection in the cultivars were 12·5, 0·5, 0·25 and 0·1 respectively. The percentage of seedling infection is directly correlated to the percentage of embryo infection. The possibility of using this technique in quarantine screening is discussed.
pp 259-262 August 1990
Three species of a vesicular-arbuscular mycorrhizal fungus,Sclerocystis, viz.,Sclerocystis pakistanica Iqbal and Bushra,Sclerocystis clavispora Trappe, andSclerocystis sinuosa Gerdemann and Bakshi, have been found to occur consistently in the agricultural fields planted to sorghum and foxtail millet in Anantapur district of Andhra Pradesh. A comparison of the morphological features of these sporocarps was made with those already reported.
pp 263-277 August 1990
The vegetational wealth of northwest Himalaya is discussed in this paper. Unlike the vegetation of eastern Himalaya, the forests are not diverse and rich. The forests here are mainly classified under (i) tropical forests, (ii) subtropical forests, (iii) temperate forests, (iv) subalpine forests and (v) alpine vegetation, primarily based on the altitude. The plant resources of the region are briefly outlined with reference to (i) wild edible plants, (ii) medicinal and aromatic plants, (iii) ornamental plants, (iv) orchids, (v) fodder resources, (vi) bamboos and (vii) other biologically interesting species. The brief phytogeographical affinities of the northwest Himalayan flora, the major threats to the flora and some conservation programmes are also discussed.