Paederia foetida — a promising ethno-medicinal tribal plant of northeastern India

The northeastern region of India constitutes one of the biodi-versity hotspots of the world. The ethnic groups inhabiting this region practice their distinctive traditional knowledge systems using biod...     

Incidence of dieback disease following fungal inoculations of sexually and asexually propagated shisham (Dalbergia sissoo)

Shisham (Dalbergia sissoo) is an important multipurpose tree with great economic importance, but this tree has been devastated by dieback disease. Seedlings and asexually propagated (cuttings) plants were artificially inoculated with four fungi (Fusarium solani, Botryodiplodia theobromae, Curvularia lunata and Ganoderma lucidum) to evaluate the potential role of these fungi in shisham dieback disease. Results at 2 years revealed that highest disease was caused by inoculation of F. solani (31.39%), followed by B. theobromae (19.042%) and C. lunata (12.22%), but no dieback disease was caused by G. lucidum. During both years, seedlings exhibited greater susceptibility to disease (17.24%) compared to cuttings (7.83%). In particular, F. solani caused more disease in seedlings (46.18%) compared to cuttings (16.61%). With the F. solani inoculations, maximum disease rate was observed at 8 weeks post‐inoculation both in seedlings (77%) and in cuttings (31%), but the maximum disease increase was observed at 4–5 weeks post‐inoculation. Analysis of variance showed significant differences among the different fungi and also between seedlings and cuttings. F. solani can be considered as a major fungal pathogen contributing to dieback disease of shisham, and asexual propagation can reduce the severity of dieback.     

Tree Planting in an Urbanizing South Africa / BOOMAANPLANTING IN VERSTEDELIKENDE SUID-AFRIKA

The title of this paper might well read “Tree planting in an urbanizing and industrializing South Africa”, because in modern South Africa industry is prominent in the urban scene. The importance of trees in the urban landscape is stressed. Purposes for which trees are used in commercial, industrial and residential areas are listed. An account is given of tree planting in boulevards and avenues, state and civic centres, car parks, bus termini, recreational parks, botanical gardens and arboreta, zoological gardens, sports enclosures and children's playgrounds. The role of trees in industrial areas is discussed and the vegetating of mine dumps described. Passing reference is made to the uses of trees on the sea front. Tree planting for economic purposes by civic authorities is briefly touched upon. The value of trees in private gardens is underlined.     

Application of Line Thinnings in Practice

The discussion covers the need to change our present system of harvesting pine timber thinnings in order to increase productivity. It points out that this productivity increase can only be achieved through technical innovation and by the introduction of machinery suited to do the job. The machinery and work methods call for a type of neutral thinning in conjunction with a selective thinning or followed by a selective thinning. The advantages of this type of thinning, as practised in this country, are illustrated.     

Micropropagation of Selected Genotype of Aloe vera L.—An Ancient Plant for Modern Industry

Aloe vera Linn. (Syn. Aloe barbadensis Mill; Gwar-patha in Hindi) belongs to family Liliaceae. The plant, for its medicinal properties, has commercial value. Some of the genotypes of Aloe vera are consumed as a vegetable and processed to make curry and other edible products. We report here on the development of an efficient method for rapid clonal propagation by shoot proliferation from axillary meristem(s) of selected germplasm of Aloe vera. Explants were pretreated with 0.1% aqueous solution of both streptomycin and bavistin separately, each for 15 min. These were surface sterilized with 0.1% aqueous solution of mercuric chloride (HgCl₂) for 4–5 min and washed several times with autoclaved water. These were kept in a chilled, sterile antioxidant (200.0 mg L^?1 of ascorbic acid, 50.0 mg L^?1 of citric acid, and 25.0 mg L^?1 of polyvinylpyrrolidone; PVP) solution and cultured on semi-solid Murashige and Skoog's (MS) medium. The bud explants produced multiple (10.3 ± 0.675/explant) shoots on MS medium containing 13.32 μM of 6-Benzylaminopurine (BAP) and 100.0 mg L^?1 of ascorbic acid, 50.0 mg L^?1 each of citric acid and PVP, with 25.0 mg L^?1 each of arginine and adenine sulphate as additives. The shoots were further multiplied by (a) repeated transfer to fresh MS medium with additives + 13.32 μM BAP, and (b) subculturing on MS medium with a lower (4.44 μM) concentration of BAP. On MS medium containing 4.44 μM of BAP and additives, a maximum number (27.8 ± 0.63) of shoots were produced. In liquid MS medium with 4.44 μM of BAP, the rate of shoot multiplication increased and the vigor of the shoots improved. One hundred percent of the cloned shoots rooted under in vitro conditions on hormone-free half-strength MS salts containing 200.0 mg L^?1 of activated charcoal at 32 ± 2°C. The cloned shoots treated with 2.46 mM of indole-3-butyric acid (IBA) or 2.473 mM of β-naphthoxyacetic acid (NOA) for 5 min rooted under ex vitro conditions in the greenhouse. The rooted plants were hardened in the greenhouse and stored under an agro-net house. The cloned plants were transferred under different field conditions at various sites in Western Rajasthan. These plants grew normally. The higher rate of shoot multiplication and easier approach of direct rooting and hardening make this method superior to the methods previously reported on cloning/tissue culture of Aloe species. From a single shoot bud, approximately 5000 plants can be produced within 180 days.     

The propagation of Ramón (Brosimum alicastrum Sw.; Moraceae) in Mayan homegardens of the Yucatan peninsula of Mexico

In the Yucatan peninsula of Mexico, Maya natives have been propagating important species for centuries. However, little documentation exists of these methods, and traditional knowledge is fading as younger generations seek work in urban centers. With growing interest in using some of these species for plantation-scale production, this knowledge should be captured to aid in propagation and cultural methods of selected species. One such species, Ramón (Brosimum alicastrum Sw.), is grown in Mayan homegardens primarily as a source of dry season forage. We conducted a survey of Mayan families in several municipalities to determine basic propagation habits and procedures for cultivating Ramón, and used this information to conduct some controlled-environment studies of reproductive ecology of the species. Our survey showed that all or most Maya grow the Ramón tree in homegardens for forage and that the tree is both cultivated from wild seedlings as well as planted on a small scale. Propagation is by seed and young seedlings are irrigated until they are established. We examined the effects of temperature on seed germination and found that maximum germination occurred between 27° and 38 °C, with best germination and growth of healthy seedlings at 33 °C. No germination occurred below 21° or above 44 °C. Simulated Maya irrigation gave a four-fold increase in growth rate of seedlings, aiding early establishment. Watering gave seedlings of greater biomass, greater stem and root length, and greater numbers and size of leaves. This magnitude of response may provide an economic return for plantation culture of Ramón for forage production.     

Incorporating forage grasses in riparian buffers for bioremediation of atrazine, isoxaflutole and nitrate in Missouri

Multi-species tree-shrub-grass riparian buffer systems have been recognized as one of the most cost-effective bioremediation approaches to alleviate nonpoint source agricultural pollution in heavily fertilized systems. However, highly concentrated herbicides in surface and subsurface water and shade cast by trees along the stream bank usually compromise the effectiveness of these systems. Greenhouse trials and field lysimeter studies were conducted to evaluate the tolerance of orchard grass (Dactylis glomerata), smooth bromegrass (Bromus inermis), tall fescue (Festuca arundinacea), timothy (Phleum pratense), and switchgrass (Panicum virgatum) ground covers to atrazine and Balance™ (isoxaflutole) plus their capacity to sequester and degrade these herbicides and their metabolites. Their ability to remove soil nitrate was also quantified. Concentrations of atrazine, Balance™ and their metabolites in the leachate, soil and plant samples were determined by solid phase extraction followed by high performance liquid or gas chromatographic analyses. Distribution of the herbicides and metabolites in the system was calculated using a mass balance approach. Herbicide bioremediation capacity of each lysimeter treatment was determined by the ratio of metabolites to parent herbicide plus metabolites. Bioremediation of nitrate was quantified by comparing nitrate reduction rates in grass treatments to the bare ground control. Based on this herbicide tolerance, bioremediation data and shade tolerance determined in a previous study, it was established that switch grass, tall fescue and smooth bromegrass are good candidates for incorporation into tree-shrub-grass riparian buffer systems designed for the bioremediation of atrazine, Balance™ and nitrate.     

Wood of Gmelina arborea in Costa Rica

New Forests - Gmelina arborea Roxb. (gmelina) was introduced in Costa Rica in the late 1960s. At the present time, gmelina is the most widely planted tree species in Costa Rica. According to...