In vitro studies on apogamy, apospory and controlled differentiation of rhizome segments of the fern, Ampelopteris prolifera (Retz.) Copel.

Apogamy was induced in the fern Ampelopteris prolifera by culturing the gametophytes on mineral nutrients supplemented with various concentrations of sucrose. Higher concentrations (5–8%) of sucrose were detrimental to prothallial growth, while in lower concentrations (2–3 %) apogamy was delayed. Gametophytic callus was induced from the germinating spores by culturing them on 2,4-D rich (3–5 mg/1) media. The differentiation of this gametophytic callus was conditioned by sucrose and auxin concentrations of the medium. In the presence of sucrose, calli responded like prothalli, while in the presence of 2,4-D, differentiation was delayed or completely inhibited. Apospory was induced on the sexual cotyledonary and juvenile sporeling leaveS. Leaves with petiole, excised from aseptically raised plants from excised cultured buds, also exhibited apospory, while no success was achieved with the excised leaves of the parent plantS. Rhizome segments of various length were cultured on media containing different concentrations of sucrose. The differentiation of rhizome segments into gametophytes or sporophytes was conditioned by the length of the rhizome segments and the sucrose concentration of the medium. The possible significance of all the results is discussed.     

The Anatomy of Stenochlaena palustris (Burm.) Bedd

The stelar anatomy of Stenochlaena palustris is described. Thestem is dictyostelic and in transverse section shows five orsix closely situated large central meristeles. Around theseare two rings of smaller peripheral bundles. These outer ringsare mainly ‘residual traces’ derived from the leaf-and root-traces. They anastomose freely and are intimately connectedwith the central system. The dictyostely of the latter is due both to leaf-gaps and tomom or lesa random perforations, the latter being the more numerous. The leaf-trace, at first binary, enters the petiole along witha large number of the smaller bundles from the stem periphery.‘Root-traces’ are given off from the base of theleaf-gaps.     

The Cytology of some Athyrium species from Northern India

The present investigation deals with the cytology of genus Athyriumfrom Northern India. Eleven species have been studied and comparisonswith the previous records are made. All the North Indian speciesare sexual and there is a lower percentage of polyploidy comparedwith the species in Ceylon. Their occurrence at high altitudessuggests that the temperate climate may be significant in thisconnexion. Polyploidy is noticed only up to the tetraploid leveland only in two cases.     

Nutrient Movement in Litter Fall and Precipitation Components for Central Himalayan Forests

The annual total litter fall in six Central Himalayan forestsranged from 2.1 to 3.8 t C ha^–1, of which 54 to 82 percent was leaf litter, 9–20 per cent wood litter and 6–14per cent other litter. In all forests the order of relativeabundance of nutrients (kg ha^-1 year^-1) in litter fall was Ca(50.8–91.6) > N (47.7–72.2) > K (22.8–37.1)> P (4.1–6.4). Leaf litter accounted for 63–95per cent of the total nutrients returned through litter fall. In these forests throughfall ranged from 71.3 to 81.4 per cent,stemflow from 0.50 to 2.16 per cent and canopy interceptionfrom 17.7 to 28.2 per cent of the gross rainfall. In the incidentrainfall the concentration and annual input of Ca was the greatestand of P the least. Canopy precipitation was richer in all nutrientscompared to incident rainfall. Net gain of nutrients from thecanopy ranged from 0.16 kg ha^-1 year^-1, for P, to 17.77 kg ha^-1year^-1 for K. Leaching was greatest for K and least for N. Ofthe total quantity of nutrients returned to the soil, 11 to46 per cent was accounted for by precipitation components. Thusprecipitation inputs play a significant role in nutrient cyclingof these forests. Himalaya, forest, litter fall, precipitation components, nutrients     

Cytology of Callus of Cryptomeria japonica

Callusing has been initiated from the cotyledons of 4-week-old seedlings of Cryptomeria japonica on Murashige and Skoog's medium supplemented with 22.8 μM IAA. Callus was grown successfully for more than 2 years on the same medium without any decline in growth vigour. The callus has shown differentiation of tracheids with reticulate thickenings but differentiation of root, shoot or whole plant has not yet been observed. Cytology of 2-month-old callus showed the presence of cells containing normal diploid chromosome complement of 2n = 22 and normal mitosis. However, the 6-month-old callus revealed majority of cells with normal diploid complement and the usual karyotype, but a few cells were noticed with aneuploid numbers ranging from 2n = 15–17. Anaphase bridges and lagging chromosomes have also been encountered.     

Colchicine Effect on the Prothalli of Goniopteris multi-lineata (Wall.) Bedd. and G. prolifera (Roxb.) with Emphasis on Abnormal Spermatogenesis in Polyploid Prothalli

Cytological investigation into abnormal sperm formation in polyploidprothalli reported earlier has been undertaken. It is establishedthat the B-type sperms are diploid and giant C type derive fromtetraploids. The spermatogenesis in tetraploid prothalli ismodified by frequent amitosis and fragmentation of the mothercell nucleus resulting in twins, triplets, and monsters withdouble or triple heads or tails; obviously the nuclear constitutionof these sperms is variable.     

Development of Caryophyllaceous Stomata in Asteracantha longifolia Nees

The development of caryophyllaceous type of stomata in Asteracanthalongifolia Nees. is typically syndetocheilic. The two crescenticsubsidiary cells and the encircling cells are derived from thesame meristemoid which ultimately gives rise to the guard cells.     

Colchicine Effect and the Production of Abnormal Spermatozoids in the Prothalli of Dryopteris subpubescens (BI.) C.Chr. and Goniopteris prolifera Roxb

Dilute colchicine solutions have been found to modify the earlystages of germination of spores in the ferns Dryopteris subpubescensand Goniopteris prolifera. When subsequently grown on soil theprothalli continued to grow abnormally and produced abnormalsperms. Certain prothalli in both species produced large sperms,possibly being diploid, and others and less normal ones producedgiant possibly tetraploid sperms. Monstrous sperms were noted in which two, three, or four bodieswere all united in front, or more rarely where the body forksinto two heads.