Seasonal behaviour of vascular cambium in Tectona grandis L. f. growing in Moist Deciduous Forests (MDF) and Dry Deciduous Forests (DDF) of Gujarat State in Western India was studied for one annual cycle. In both the forests active cambial cell division and simultaneous differentiation of xylem and phloem started in June when the dormant shoot buds opened. In MDF cambial cell activity reached its peak in August-September and ceased in October; in DDF it ceased in November after reaching a peak in July-August. Maximum radial growth in trees of both forests occurred during the monsoon period. In both forests, phloem differentiation ceased before xylem differentiation. During dry months and the leafless periods the cambium remained dormant. Xylem mother cells next to the mature xylem in MDF underwent differentiation into xylem elements following the onset of periclinal divisions in March. In both forests, the seasonal anatomical changes associated with the cambium closely followed the phenology of the tree and local climatic conditions.

A locally isolated strain of Trichoderma harzianum was studied for production of xylanase (EC 3.2.1.8) using lignocellulosic substrates for solid-state fermentation. Among the different substrates used, wheat straw produced the highest yields (146 IU/ml). The influence of temperature, pH, moistening agents, moisture level, carbon sources, nitrogen sources, pretreatments and metal ions were evaluated with respect to xylanase production. Highest xylanase production was obtained using wheat straw after 12 days of incubation. Different substrate combination ratios and the effect of particle size were also checked against xylanase production. Maximum xylanase production was observed in a wheat straw/rice straw ratio of 1:1, with a particle size of 0.45–0.5 mm. Media supplementation with xylose as a carbon source in a ratio 1:5 (carbon source/substrate) gave maximum activity (157 IU/ml). Nitrogen supplementations from yeast extract produced xylanase activity of 141 IU/ml. Optimum xylanase production was observed at 30°C and pH 5.0. Xylanase production was enhanced in the presence of Ca²⁺ and Zn²⁺ ions. Ammonium sulfate fractionation (20–80% saturation) of partially purified xylanase yielded 76.5% of the enzyme with a 3.53-fold purification. The molecular weight of xylanase was found to be ca. 29,000 Da by SDS–PAGE.