Effect of seed mass on emergence and seedling development in Pterocarpus marsupium Roxb.

We investigated the effect of seed mass on emergence, seedling survival and growth ofPterocarpus marsupium Roxb., a medium to large, commercially valuable and deciduous tree species. Among the three size classes viz. small （10-12 mm）, medium （13-15 mm） and large （16-17 mm）, the maximum proportion, of seed by number （54.12%） and dry weight （51.87%） was recorded, in the medium size seed class. Seed length and seed width were greatest in the large seed class （16.50 mm, 7.33 mm） followed by medium （13.50 mm, 5.60 mm） and small （11.37 ram, 3.66 mm）. Similarly, hundred seed weight （100 sw） varied from a maximum of 12.92 g in the large seed class to intermediate 10.95 g in the medium seed class and minimum of 7.02 g in the small seed class. The large seed size showed maximum emergence and shoot length over the medium and small seed class. After six months of growth, significant variations due to seed size were also observed for the growth and dry weight of P. marsupium seedlings. Seedling vigour, expressed in terms of height, collar diameter, number of leaves and dry biomass, was sig- nificantly affected by seed class. Seedlings that emerged from large seeds showed better growth and produced heavier seedlings as compared to medium and small seeds.

An improvised in vitro vegetative propagation technique for Bambusa tulda： influence of season, sterilization and hormones

Season and concentration of sterilizing agents play a significant role for establishment of aseptic in vitro shoot cultures and sprouting of nodal explants from field growing culms of bamboo species. In the present investigation the nodal segment explants of Bambusa tulda Roxb collected in different seasons and treated with various concentrations of HgC12 showed significant variation in aseptic culture establishment and bud break. The rainy season （July-August） recorded with highest of 78% aseptic culture establishment whereas autumn recorded with lowest 46%. Summer and winter seasons emerged to be the best period, registering 〉 60% in vitro bud break. On the other hand, the autumn season had the lowest value for bud break, i.e. 42%. Among different doses of sterilizing agent tried, HgC12 0.1% found to be suitable for maximum aseptic culture establishment （66%） as well as bud break （59%）. However, among the interactions, summer season and the dose of 0.1% HgC12 exhibited maximum of 73% response for both aseptic culture establishment and bud break. MS medium （liquid） enriched with 5.0 μM BA ＋5.0 μM Kn [Kinetin （N6-Furfuryladenine）] with additional supplementation of 100 μM glutamine ＋ 0.1 μM IAA supported a maximum in vitro shoot multiplication of 4.75 fold. The proliferated shoots were successfully rooted on MS medium （liquid） supplemented 40 μM coumarin. The plantlets transferred to the polythene bags showed 98% survival.

Biochemical changes associated with flowering in Bambusa arundinacea and Bambusa nutans

Biochemical changes associated with flowering in Bambusa arundinacea Linn and Bambusa nutans Wall.ex Munro were analyzed.Gregarious flowering was initiated in natural areas and plantations of B.arundinacea in late 2014 and reached full bloom in early 2015,whereas sporadic flowering recorded during 2014–2015 in vegetatively propagated plants of B.nutans.Leaf and nodal shoot samples from flowering culms/shoots and nonflowering culms/shoots were collected in February 2015 at the initiation of fruit filling,then analyzed and compared for soluble sugars,phenols and peroxidase activity.In both species sugars were higher in leaves of flowering culms/shoots and lower in nodal shoots of flowering culms/shoots compared to the nonflowering.Phenols were lower in leaves and nodal shoots of flowering B.arundinacea,but higher in leaves and decreases in nodal shoots of B.nutans.Peroxidase activity increases in leaves and nodal shoots of B.arundinacea after flowering but increases in nodal shoots and decreases in leaves of B.nutans.