Volume 99, Issue 6
December 1989, pages 517-591
pp 517-522 December 1989
Physiological responses of pearl millet and sorghum to water stress were compared for better understanding of crop adaptation in drylands. Pearl millet (MBH-110) and sorghum (CSH-6) were raised in pots and were subjected to short term water stress at anthesis stage. Water stress decreased leaf water potential, rates of stomatal conductance, photosynthesis and transpirations and transpiration efficiency in flag leaves relatively more in sorghum than in pearl millet. Stomatal conductance and transpiration rates recovered quicker in pearl millet than in sorghum in 24 h after rewatering. Dry season accentuated the water stress effects. Transpiration efficiency of pearl millet was more responsive to increase in atmospheric moisture. The physiological responses explain the better adaptation of pearl millet to drier regions than of sorghum.
pp 523-527 December 1989
Chickpea seedlings (Cicer arietinum L.) were used to initiate callus on B5 medium supplemented with 2 mg/l 2,4-dichlorophenoxyacetic acid+0·5 mg/l NAA and kinetin. After a month's growth the healthy callus was transferred to a similar medium supplemented with different concentrations of the pesticide Rogor (O, O-dimethyl-S-methyl carbamoyl methyl phosphorodithioate). After one month in the pesticide medium most of the cells exposed to higher concentration died, but a few cells remained healthy. In a control medium the cells remained healthy over the same period. The pesticide treatment inhibited the protein content and the activity of the enzyme amylase, whereas an increase in the activity of peroxidase was observed. The surviving pockets of pesticide exposed cells were exercised and transferred to a medium that caused shoot initiation and later to a medium that caused root formation from the base of the shoot. Plants were taken through to maturity in soil. The resistant cell line contained high levels of proteins and peroxidases compared to control. Additional bands of peroxidase isozymes were observed in the resistant line.
pp 529-537 December 1989
Thirteen dicot weed species comprising C3, C3−C4 and C4 photosynthetic types were examined in an attempt to understand relationships between leaf anatomical characteristics and net photosynthetic CO2 uptake. Plants grown on field soil in open air under natural sunlight were used for measurements of net photosynthetic CO2 uptake and leaf anatomical characteristics. The data on net photosynthetic rates and leaf anatomical features of test plants showed consistent grouping into C3, C3−C4 and C4 photosynthetic types. Overall the C3−C4 group of plants invariably exhibited an intermediate nature in all leaf anatomical characteristics as well as photosynthetic rates between those of C3 and C4 groups of plants.
Correlation analysis showed significant relationships between photosynthetic rates and some leaf anatomical characteristics across diverse photosynthetic types but these were insignificant among different species of the same photosynthetic type. The results indicate that differences in internal leaf characteristics between different photosynthetic types are probably important factors contributing to differences in their net photosynthetic rates. A definite relationship between photosynthetic capacity to fix CO2 and some leaf anatomical characteristics among diverse photosynthetic type of plants indicate selection for plant species or genotypes with efficient leaf anatomical characteristics could be possible to improve photosynthetic efficiency and, in turn, plant productivity.
pp 539-546 December 1989
In view of the sun and shade adaptations of plants to semi-arid climatic conditions investigations were undertaken withErythrina variegata Lam. The studies revealed that shading decreased root and shoot growth, leaf density, leaf area, specific leaf weight, relative growth rate and relative leaf growth rate. Consequently the dry biomass accumulation was adversely affected in shade grown plants. Synthesis of chlorophyll including Chla and Chlb were promoted in the shade grown plants, so as to trap the available sun energy efficiently under shade condition. The Chla/b ratio was decreased in shade grown plants as compared to sun plants. Total soluble protein was reduced, which could be related to the lowered net photosynthetic rate. Thein vivo nitrate reductase (EC 1·6·6·1) activity, an indicator of nitrate utilization was also significantly reduced. Both reduced enzyme activity and net photosynthetic rate could be attributed to the lowered whole plant biomass productivity. The increased stomatal diffusive resistance in shade plants, is associated with the low rate of transpiration. It is concluded that the biomass productivity ofErythrina variegata Lam. under shade condition is drastically reduced by low irradiance.
pp 547-556 December 1989
The pericarp ofAbelmoschus esculentus is differentiated into 3 distinct zones—the epicarp, mesocarp and endocarp. The epicarp is a product of outer epidermis and hypodermal parenchyma of the ovary wall. The growth of epicarp results from increase in the volume of cells of the periphery below the outer epidermis. In a mature pericarp the epicarpic cells become enlarged, vacuolated, thick walled and resemble collenchyma. The parenchymatous mesocarp is derived from the inner zone of ground parenchyma of the ovary wall. The large and vacuolated parenchyma of the developing mesocarp appear disorganised at maturation of the fruit. An interwoven pattern of endocarp is composed of sclerenchyma and develops from the inner epidermis together with inner sub-epidermis of the ovary wall. The dehiscence of ripe capsule ofAbelmoschus esculentus is the result of differentiation of mechanically weak cells in the median plane of each carpel, as well as in the central column and porus endocarp.
pp 557-565 December 1989
Leaf anatomy of 13 species of Indian mangroves belonging to 11 genera and 9 families of the dicotyledons is presented. Leaves are dorsiventral in all the species except inLumnitzera racemosa where they are isobilateral and amphistomatic. The cells of the lower epidermis are larger than those of the upper surface. Stomatal type and size are considered. Water storage tissue is present in all the species exceptAegialitis rotundifolia. The significance of the findings are highlighted in light of the earlier available information and a key is constructed based on the leaf anatomical characters.
pp 567-578 December 1989
A revision of the genusBlachia Baill. (Euphorbiaceae) for India and adjoining countries is presented. Three species are recognized.Blachia reflexa Benth. is conspecific withBlachia umbellata (Willd.) Baill., whileBlachia denudata Benth. represents a subspecies ofBlachia andamanica (Kurz) Hook. f.
pp 579-583 December 1989
Selection for vegetable and seed types in cluster bean has necessitated a change in the resource allocation pattern between the seed and pod features. In the vegetable types where selection has been primarily for the pod characteristics, several features such as pod length, individual pod weight, pod coat weight (also referred to as packing cost), packing cost per unit seed weight, packing cost per unit seed number and packing cost per unit pod length indicate a substantial allocation of resource to the pod than the seed. In the seed types, the allocation is biased to seed biomass per se. Though the seed number per pod was same in the vegetable and seed types, the correlation between the seed number per pod with pod length, pod weight, individual seed weight and packing cost was negative for vegetable type, while, it was positive in the seed types. Z transformation considering packing cost per seed weight and seed number per pod, and pod weight to seed weight and packing cost per unit seed number segregated the two types into distinct quadrants. The two contrasting allocation patterns may also represent alternate strategies of cluster bean against seed predators in the wild habitats.
pp 585-591 December 1989
The softwood grafting in jackfruit is a simple and rapid method of vegetative propagation. A success varying from 33·33–80% has been reported in this method. Matured scion sticks of 6 months old recorded significantly highest sprouting (73·33%) and survival (68·33%) of the grafts. With the increase in the length of scion sticks from 2·5–10cm, the percentage of success also increased from 6·66–58·33%. The scion sticks of 7·5 and 10 cm length gave the highest success (58·33%). No significant difference in success was observed with defoliated and undefoliated scion sticks. The jackfruit scion sticks can be stored in moist sphagnum moss, polybags, moist gunny cloth or moist news paper up to 3 days.