Arbuscular mycorrhizal colonization and nodulation improve flooding tolerance in Pterocarpus officinalis Jacq. seedlings.

Pterocarpus officinalis (Jacq.) seedlings inoculated with the arbuscular mycorrhizal fungus, Glomus intraradices, and the strain of Bradyrhizobium sp. (UAG 11A) were grown under stem-flooded or nonflooded conditions for 13 weeks after 4 weeks of nonflooded pretreatment under greenhouse conditions. Flooding of P. officinalis seedlings induced several morphological and physiological adaptive mechanisms, including formation of hypertrophied lenticels and aerenchyma tissue and production of adventitious roots on submerged portions of the stem. Flooding also resulted in an increase in collar diameter and leaf, stem, root, and total dry weights, regardless of inoculation. Under flooding, arbuscular mycorrhizas were well developed on root systems and adventitious roots compared with inoculated root systems under nonflooding condition. Arbuscular mycorrhizas made noteworthy contributions to the flood tolerance of P. officinalis seedlings by improving plant growth and P acquisition in leaves. We report in this study the novel occurrence of nodules connected vascularly to the stem and nodule and arbuscular mycorrhizas on adventitious roots of P. officinalis seedlings. Root nodules appeared more efficient fixing N(2) than stem nodules were. Beneficial effect of nodulation in terms of total dry weight and N acquisition in leaves was particularly noted in seedlings growing under flooding conditions. There was no additive effect of arbuscular mycorrhizas and nodulation on plant growth and nutrition in either flooding treatment. The results suggest that the development of adventitious roots, aerenchyma tissue, and hypertrophied lenticels may play a major role in flooded tolerance of P. officinalis symbiosis by increasing oxygen diffusion to the submerged part of the stem and root zone, and therefore contribute to plant growth and nutrition.

The characteristics and economic importance of Pterocarpus angolensis in D.C. Botswana.

Pterocarpus angolensis grows throughout northern Botswana and may be found in all woodland types as well as in evergreen and deciduous forests. It is among the few indigenous trees that thrive in the deep Kalahari sands. P. angolensis produces a hard wood timber of attractive appearance. Due to its flexibility, resistance and lightweight, the communities in Botswana use the species for making door frames, window frames, canoes, canoe peddles, spear handles for use in game hunting, fishing and general construction. The community also use it as a carving and sculpting medium. Traditionally, all parts of the tree are used for medicinal purposes.

[A new medicinal plant Pterocapus indicus].

It has been 70 years since Ptercapus indicus Willd. was introduced into China. The red sap from its incision of the bark becomes a kind of red crystal after some hours of exposure to air, which is used as an astringent and against other diseases. Its physicochemical properties, elements and amino acids have been analysed. The structural analysis shows that the crystal is a macromolecular compound of tannic condensation and glucoside.