Volume 96, Issue 1
March 1986, pages 1-78
pp 1-7 March 1986
Quantified chromatographic data on the distribution pattern of phenolic constituents in 15 species ofBauhinia expressed as synthetic numerical indices and polygons indicate a close biochemical kinship among them and do not warrant the splitting of the genus, as has been done on morphologic grounds. However, the grouping of the species, based on similarity coefficients clustered successively by WPGM, does not conform to the grouping on traditional grounds.
pp 9-15 March 1986
Root acetylene reduction activity and number of diazotrophs varied significantly with wheat varieties grown under field conditions. Rhizoplane contained 2–3 times more nitrogen fixing bacteria compared to rhizosphere. The two isolates 8W and 96W out of 148, showed highest nitrogenase activity in solid and semisolid media under laboratory conditions. These were identified asBacillus sp. (8W) andPseudomonas sp. (96W). The acetylene reduction activity of these bacteria were highest at 96 hr of incubation, 30°C and neutral pH. Increased nitrogenase activity was recorded with sodium malate (50 mM), yeast extract (0·2 g/l), ammonium chloride (5 mM) and vitamins. Pot house studies on wheat using diazotrophs as seed inoculants showed a positive response in number of N2 fixing bacteria, root acetylene reduction activity and dry matter yields.
pp 17-24 March 1986
The occurrence ofPorella platyphylla (L.) Pfeiff. in India was so far doubtful, but the present investigations have now established its definite representation in western Himalaya. The scanning electron microscope details of spores have been studied for the first time in this species showing characteristic sporoderm architecture.
pp 25-36 March 1986
Three year old open grown pine saplings were selected. Three whorls of shoots were begun in one year. The species thus exhibits a recurrent flushing pattern. Two orders of shoots were recognised on the main leader during the study period of one year. Shoots produced at lower canopy levels attained less extension growth and fewer and shorter needles compared to shoots at higher canopy levels. The growth characteristics of shoots indicated shade intolerant nature of the species. The fascicles of 3 flushes appearing at different times of the year had different patterns of fall and life expectancy. The adaptive strategy of the growth pattern with recurrent flushing and short longevity of the needles are discussed and related to faster growth rate ofPinus kesiya in an early successional environment.
pp 37-40 March 1986
In a systematic analysis of water hyacinth leaves collected from two different water bodies as compared with those collected from non-polluted water body, it was found that there was a considerable variation in the elemental analysis as well as in the chlorophyll and protein content of the leaves. The ash content and various inorganic elements like silica, iron, aluminium, calcium and magnesium were found to be significantly higher in leaves collected from polluted areas. However, phosphates and sulphates did not show significant changes in the ppm levels of the control and test samples. Water samples were also collected from these sources and analysed for the extent of pollution by determining total solids, hardness and alkalinity. Ionic concentrations of Mg2+, Ca2+ and nitrogen were also studied. These studies enabled us to conclude that high levels of either calcium, magnesium or silica content in normal plants are indicators of aquatic pollution.
pp 41-48 March 1986
Nectar composition (sugars and amino acids) of 100 species representing 83 genera from 34 families of angiosperms have been studied. The distribution of the 3 common sugars viz., sucrose, fructose and glucose in nectars of the species studied can be broadly divided into 6 types, based on the presence or absence of any one of the sugars viz sucrose-glucose-fructose, sucrose-glucose, sucrose-fructose, glucose-fructose, glucose and sucrose types with some variations. α-Amino acids were processed in 85 species. Distribution of amino acids was studied in some species and was found to be useful in detecting flower visitors.
pp 49-53 March 1986
Soluble and wall-bound activities of acid phosphatase, β-glucosidase, α-galactosidase and invertase in the ovules ofGossypium arboreum L. andGossypium hirsutum L. are implicated in the hydrolysis and translocation of substrates during pre- and postanthesis phases. The physiological functions of these hydrolytic enzymes are discussed in relation to early ovule development and cotton fibre differentiation.
pp 55-61 March 1986
Hypocotyl and stem explants of 12 cultivars of mothbean callused and differentiated embryoids/shoot buds on basal medium devoid of growth regulators. Cotyledon and leaf explants failed to differentiate. Factors that influence differentiation of embryoids/shoot buds such as pre-conditioning of the germinating seeds with cytokinins and antiauxins, size and orientation of the explant on the medium and use of thin-layer peelings as explant were investigated. The shoot buds/embryoids developed into full fledged plantlets with roots on the same medium and were reared to maturity in field.
pp 63-69 March 1986
The seed dry weight ofQuercus leucotrichophora A. Camus. ex. Bahadur (banj oak) were much larger than the seeds ofPinus roxburghii Sarg. (chir pine) (1463 and 87 mg per seed). The responses of chir pine, an early successional species, and banj oak, a late successional species were compared in terms of seed germination. Seed germination was observed on single factor gradients of temperature, water stress, seed desiccation and light qualities. The suppression of germination caused by continuous dark and far-red was greater for chir pine than in banj oak. Compared with banj oak, chir pine seed germination showed wider response breadth on gradients of water stress and seed desiccation and narrower response breadth on the gradient of light quality.
pp 71-78 March 1986
Comparative embryology ofEchinochloa colonum (Linn.) Link andEchinochloa crusgalli (Linn.) Beauv. is described. The anther wall comprises the epidermis, fibrous endothecium, a middle layer and uniseriate glandular tapetum. Microspore tetrads are isobilateral inEchinochloa crusgalli but they may occasionally be linear, T-shaped, decussate or intermediate besides being isobilateral inEchinochloa colonum. The hemianatropous ovule is pseudocrassinucellate and bitegmic. Embryo sac development conforms to the monosporic, Polygonum type. Endosperm development is nuclear. The development of the embryo is irregular and characterised by the formation of diagonal cell walls in the quadrant and octant proembryo. Both the integuments as well as the nucellus degenerate in mature caryopsis. The mature embryo is about half the length of the caryopsis and is of the panicoid type. The results have been discussed in light of the earlier work onEchinochloa and other members belonging to the tribe Paniceae.