Volume 89, Issue 4
August 1980, pages 237-321
pp 237-241 August 1980
Karyotype ofEupatorium adenophorum (2n = 51),Eupatorium riparium (2n = 51) andEupatorium odoratum (2n = 60) has been studied. Their T.F. values are 46 · 14%, 49 · 14% and 46 · 40% whereas the complement length is 64 · 61 µ, 51 · 59 µ and 89·82 µ respectively. Based on x = 10 and 17 and meiotic behaviour, the first two species have been suggested to be autotriploids and the third as allohexaploid. These species were introduced into India from America and became successful colonizers and weeds. Polyploidy, agamospermy, vegetative reproduction and genie heterozygosity confer an advantage in competition.
pp 243-256 August 1980
Studies on growth and grain yield of rice var:Jaya as influenced by graded levels of N and time of N application under continuous shallow submergence and/or cyclic submergence, have shown that the growth and dry matter production after flowering and consequently the grain yield of rice was significantly more under continuous shallow submergence than under cyclic submergence. The optimum dose of N for rice var:Jaya under conditions of these experiments was around 140 kg/ha. Panicle production and grain number per panicle increased significantly upto 150 kg N/ha, while there was a decline in panicle weight beyond 100 kg N/ha. Excessive N application beyond 150 kg/ha also resulted in more of spikelet sterility. The results indicate that under cyclic submergence, a minimum of three split applications of N are necessary, although the effect of two or three split applications were at par, under continuous shallow submergence.
pp 257-267 August 1980
Nutrient uptake studies in rice varietyJaya as influenced by graded levels of N and time of N application under continuous shallow submergence and/or cyclic submergence, have shown that the N-uptake increased linearly with increasing levels of N application up to 200 kg N/ha and that the total N-uptake was 14% more under continuous shallow submergence than in cyclic submergence. The grain nitrogen content was highest, when nitrogen was applied in two split doses at planting and panicle initiation. The apparent recovery of N was maximum (54%) at 100 kg N/ha, beyond which there was a decline in percentage recovery of applied nitrogen. Split application of N and continuous shallow submergence resulted in higher recovery of added nitrogen leading to better uptake of P and K, as well.
pp 269-281 August 1980
Air spora over groundnut fields at Visakhapatnam was studied for a period of one year, i.e., from 1st June 1974 to 31st May 1975, using a ‘hirst spore trap’ installed with its orifice at 0·5 m above the ground level. More than 60 fungal spore types, hyphal fragments, pollen grains, epidermal hairs, insect parts and other inorganic particles were observed on the exposed trap slides. Seasonal and diurnal periodicities and per cent contributions to the total air spora were recorded for 38 components.Cladosporium was the most dominant spore type contributing 47·32% to total air spora. Basidiospore and ascospore types occurred mainly during rainy season while most of the conidial types occurred in high numbers during winter. Ascospores, basidiospores, conidia ofFusariutn and insect parts showed night peaks while most of the conidial types had peaks around noon. Based on the diurnal peak hour different spore types were grouped into eight types. Some spore types showed marked seasonal variations in their diurnal periodicity pattern. Most of the conidial types occurred in higher numbers when the temperatures were in the range of 28–33° C and relative humidities of 60–75%. Rain had a profound effect on the air spora.
pp 283-289 August 1980
Spray treatment of rice seedlings with three heavy metal salts and four amino acids 2 days before inoculation withHelminthosporium oryzae reduced brown spot symptoms by 23 to 52 % and 36 to 82 % respectively. Among the heavy metal salts tested, silver nitrate appeared to induce stronger effect than others. In most cases the lower concentration yielded better results. The situation was just the reverse for the amino acids. Among them DL-methionine gave maximum protection being closely followed by DL-norleucine. Different treatments affected both the components of brown spot symptoms, i.e. the number of lesions and lesion size. Resistance induced in rice seedlings appeared to function through (i) a reduction in the number of infection and (ii) an inhibition to lesion expansion. Those compounds which showed better effects in these respects gave better protection to the seedlings.
pp 291-299 August 1980
Rice necrosis mosaic virus was observed in rice cultivarTaichung (Native) 1 at maximum tillering stage. The disease was transmitted by sap and soil.Nephotettix virescens, Nephotettix nigropictus andNilaparvata lugens failed to transmit the disease. Thermal inactivation point, dilution end point and ageingin vitro have been studied. Yield reduction due to this virus varied from 12·7 to 100% on different rice cultivars tested. Disease was more common in upland and directly seeded crop. The virus produced granular x-bodies in inner epidermis of leaf sheath of infected plants.
pp 301-306 August 1980
Penicillium crustosum requires Fe, Zn, Cu, Mo, B and d (+) biotin for its growth. It does not require the following trace elements and organic growth factors: Mn, Ca, Co, W, Ga, Sc, thiamine HC1, pyridoxine HC1,i-inositol, adenine sulphate, ascorbic acid, folic acid, guanine HO, nicotinamide, riboflavin, uracil, choline chloride and xanthine. In the deficiency of essential trace elements the mycelial dry weight is reduced, the contents of mycelial tips get vacuolised and exhausted, septa are formed at shorter intervals and sporulation is inhibited. Biotin deficiency also causes similar symptoms besides formation of distinct septa in conidiophoral apparatus with vacuolised contents.
pp 307-313 August 1980
The ferns and fern-allies of Nagpur block (Chamoli Garhwal), Western Himalayas are discussed. In all 79 species (74 ferns and 5 fern-allies) have been collected of which eight species are new record for the western Himalayas.Botrychiutn daucifolium have been recorded for the first time from the Himalayas. Ecological observations for each species have been recorded. This region is rich in epiphytic vegetation. Among the fern-alliesLycopodium lucidulum andL. setaceum constitute a part of epiphytic vegetation. The ferns and fern-allies of the region are more akin to Eastern Himalayan species as 81% species are common to both the regions.
pp 315-321 August 1980
Changes in levels of macromolecular constituents and activities of some hydrolases and oxido-reductases have been studied in the developing embryos of okra,Abelmoschus esculentus. The hydrolases include acid and alkaline phosphatases, acylesterase, α- and β-glucosidases. Oxido-reductases studied are malate dehydrogenase, peroxidase and IAA-oxidase.