Mohinder Pal

Variation in Shoot Anatomy and Rooting Behaviour of Stem Cuttings in Relation to Age of Donor Plants in Teak (Tectona grandis Linn. f.)

Shoot anatomical features viz., number of vessel elements, width and length of vessel and fibre elements were studied in relation to juvenility/maturity of teak (Tectona grandis Linn. f.). The findings show significant differences in these features, which indicates that variation in shoot anatomy can be used as a reliable indicator of juvenility/maturity in teak. The effect of age of donor plants and application of auxins on adventitious root formation in single noded leafy stem cuttings of teak was also investigated. Aging of donor trees suppressed rooting and sprouting of cuttings, but increased callus formation at the base of cuttings. Per cent rooting and per cent sprouting in cuttings decreased as age of donor plants increased from 2-months to 15-years and up to 30-years. IBA treatment promoted per cent rooting as well as per cent sprouting, NAA promoted only rooting and it suppressed sprouting. The effect of auxin treatment on rooting and sprouting of teak stem cuttings varied with the age of donor plants. Auxin and its concentration, which suppressed rooting and sprouting in cuttings of younger donor plants, actually promoted rooting when cuttings were taken from more mature donor plants. It appears that the auxin requirement for causing and promoting rooting in teak cuttings increased with increasing age of donor plants. The higher auxin requirement for causing and promoting rooting in cuttings of older trees may be due to a decrease in the content on endogenous auxins or decreased sensitivity of aging tissues to rooting promoters and /or accumulation of inhibitory substances which inhibit rooting.

Diurnal changes in chlorophyll fluorescence in four species of bamboo

Diurnal changes in chlorophyll fluorescence characteristics in leaves of four bamboo species (Guadua angustifolia, Bambusa tulda, Dendrocalamus giganteus and Dendrocalamus strictus) grown under nursery conditions were recorded in June 2001. Photochemical efficiency of photosystem (PS) 2 measured as Fv /Fm ratio, varied with species and with the time of observation. Absolute parameters of chlorophyll fluorescence (F0, Fm and Fv) and Fv /Fm ratio were increased significantly from morning (1000 h) to afternoon (1600 h) in all species. G. angustifolia and B. tulda showed midday depression in Fv /Fm ratio at 1400 h while the other two species showed only constant values of Fv /Fm ratio for one hour. Hence, the chlorophyll fluorescence characteristics and midday depression in Fv /Fm ratio is species specific.

PATTERNS OF CRYSTAL DISTRIBUTION IN THE WOODS OF MELIACEAE FROM INDIA

A detailed wood anatomical survey of 42 species of Meliaceae from India has been made with a view to study the distribution pattern of different types and location of crystals. Interestingly, all the IAWA features of prismatic crystals were found in this family. The confusion regarding presence of crystals in fibres or axial parenchyma strands is clarified.