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Subject: Botany × Author: KAU × End date: 1993 × Start date: 1993 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Collection cataloguing and evaluation of rouwolfia spp.
    (Department of Agricultural Botany, College of Horticulture,Vellanikkara, 1993) Narayanan, A K; KAU; Luckins Babu, C
    A study on 'Collection, cataloguing and evaluation of Rauwolfia spp' was conducted in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during 1991-93, with the objectives of understanding the distribution pattern of various species of Rauwolfia in Kerala, detailed descriptive study of the morphological and anatomical characters of the different species of Rauwolfia and a preliminary comparative evaluation study for the total alkaloids in roots and the chlorophyll content of aerial parts. Survey of 10 geographic locations of Kerala from North to South was conducted and four species of Rauwolfia were collected. Nine ecotypes of R. Serpentina and four ecotypes of R. tetraphylla were also collected. Different species were compared based on 60 morphological characters, 15 anatomical characters and three characters of pollen grains. Evaluation for total root alkaloids was done using chloroform as solvent and determination of total chlorophyll content was done using acetone as solvent. The study on distribution aspects showed that R. serpentina was widely distributed in Kerala but the frequency of occurrence was low, while R. tetraphylla was widely distributed in non-forest areas only, with a higher frequency of occurence. R. densiflora and R. beddomei are in a state of near extinction while R. micrantha was almost disappeared from Kerala. Morphological and antomical characters and the morphology and viability of pollen grains showed wide variability among different species of Rauwolfia. Characters in addition to that available in the literature, for identifying the four species of Rauwolfia are suggeated. It is seen that chances are there for the occurence of higher ploids of the same species having higher alkaloid content, in Rauwolfia. Total alkaloid content of roots, chloroform extract and total chlorophyll content of aerial parts varied with different species and ecotypes of Rauwolfia. The conditions for the higher root alkaloid production in R. sepentina may not be favourable for the alkaloid production in R. tetraphylla. The chloroform extract and total chlorophyll content of aerial parts were negatively correlated to the total root alkaloid content in all the species of Rauwolfia. The relationship between these was found to be “Total root alkaloid content= 2.047 – 0.016 x chloroform extract of aerial parts =2.304–1.434 x total chlorophyll content of aerial parts” The relationship can be effectively utilized in the estimation of root alkaloid, in Rauwolfia spp., even at the early stages of growth, without uprooting the plants.
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    ThesisItemOpen Access
    Artifical induction of polyploidy in Cucumis sativus L
    (Department of Agricultural Botany, College of Agriculture, Vellayani, 1993) Girish Kumar, KG; KAU; Chandramony D
    An investigation entitled “Artifical induction of polyploidy in Cucumis sativus L. was carried out as two separate experiments. Experiment I, was (in-vivo study) was carried out at the College of Agriculture, Vellayani during the period September 1991 to February 1991. Experiment II (in-vitro study) was carried out at the Tissue culture laboratory attached to Department of Pomology, College of Horticulture, Vellanikkara during the period January 1991 to july 1991. The main objective of Experiment I was to study the effect of colchicine for inducing polyploidy in seed, seedling and apical bud treatments. Objectives of Experiment II were to standardise a suitable medium for embryo culture and to study the effect of colchine on proembryos, mature embryos and dry seed embryos under in - vitro conditions. Experiment I was laid out in RBD with two replications. Experiment II was carried out in CRD with three replications. The two varieties of Cucumis sativus used for the present study were Seethal and Delila. The abstract of results is given below. Experiment I Survival of plants in both Seethal and Delila was significantly affected by increasing colchicine concentration 0.2 to 0.4 per cent and with increasing period of treatment from two to six hours. Survival was significantly low in apical bud treatment. Maximum survival was noticed in seed treatment of colchicine 0.2 per cent for a period of four hours. At early growth stage significant reduction was noticed in length of vine, number of branches per plant and number of leaves per plant along with the increase in colchicine concentrations, from 0.2 to 0.4 per cent, and period of treatment, from two to six hours. Seed treatment gave maximum value for these parameters in both varieties except number of leaves in Delila. These variations seen during early growth stages were found to be diminishing at later growth stage (60 days growth stage). Delay in both male and female flower opening along with significant reduction in number of male and female flowers was noticed in higher colchicine concentrations and in lower period of treatments. Mode of treatment did not exert any significant influence on number of days taken for flower opening and total number of flowers produced per plant in both varieties except on number of days taken for female flower opening in Seethal in which by apical bud treatment maximum delay was noticed. With increasing colchicine concentration from 0.2 to 0.4 per cent and period of treatment from two to six hours significant increase in stomatal length was noticed in both varieties. Mode of treatment exerted no significant influence on stomatal length. All the fruit characters ie. Number of fruits per plant, length of fruit, girth of fruit and weight of fruit studied, were not significantly influenced by the treatments tried. In both varieties pollen size and sterility increased considerably with increasing colchicine concentration. Apical bud treatment gave significantly high values for pollen size and pollen sterility in Delila. Seed treatment recorded minimum pollen size and pollen sterility. Cytological studies were conducted in the root tips of colchicine treated seeds and metaphase and anaphase stages were obtained in the normal diploid cells. But the enlarged colchicine affected cells showed very poor stainability. Eepeiment II Standardisation of a suitable medium was carried out by using MS medium as the basal medium. MS medium supplemented with 0.1 mg/L of IAA was found suitable for embryo culture. Three types of embrayo viz., pro-embryo, mature embryo and dry seed embryo were used for embryo culturing. Embryogenesis was delayed significantly with increase in colchicine concentration from 0.02 to 0.04 per cent in both varieties. When pro-embryos were used for inoculation significant delay was noticed for embryogenesis in both varieties. Regeneration of calli was reduced significantly with increase in colchicine concentration. Pro-embryos gave lowest and dry seed embryo gave highest regeneration percentage in both varieties. Length of plantlet and number of leaves produced per plantlet in culture tubes were reduced significantly in the higher levels of colchicine concentration. Pro-embryos gave lowest and dry seed embryos gave highest values with respect to these parameters. Plantlets from pro- embryo showed lowest survival under green house conditions in both varieties. Colchicine concentration exerted no significant influence in Seethal. But in Delila with increasing colchicine concentration from 0.02 to 0.04 percent, survival of plants in green house reduced significantly. Day of treatment had no significant influence in all the parameters studied. On the basis of present study it can be concluded that different concentrations of colchicine, different periods of treatment and different modes of colchicine treatment can induce significant changes in the survival of plants, cytomorphological characters of the plants and pollen sterility. With increasing colchicine concentration and period of treatment the variations increased progressively. But considering the lethal effects as reflected on the survival of plants, 0.2 per cent colchicine application for two hours by seed treatment is desirable under in-vivo condition. Under in-vitro condition use of dry seed embroyo is best for embryo culture which can be successfully carried out by using MS medium modified with 0.01 mg/L of IAA. Colchicine 0.02 per cent can be used for the induction of polyploidy under in-vitro conditions. Since it is effective in producing variations with minimum deleterious effects.
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    ThesisItemOpen Access
    Cytogenatic analysis in kacholam
    (Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1993) Rekha, K; KAU; Viswanathan, T V
    The present study on cytogenetics of Kaempferia galanga L. in relation to seed set was undertaken at the Department of Agricultural Botany, College of Horticulture, Vellanikkara during the period 1991-93. A local selection ‘Vellanikkara’ grown under garden of AICRP on Medicinal and Aromatic Plants was used for the study. The major objectives were to confirm the existing reports on chromosome numbers, to determine the nature of pliody based on meiotic studies and to find out reasons for seedlessness in the crop in cytology and floral biology. The procedure for karyotype studies in Kaempferia was standardized. Pre-treatment of the roots in – bromonaphthalene for hours at 40C followed by fixation in Carnoy’s fluid for 24 hours and staining overnight in Snow’s carmine were effective in getting best cytological preparations. Mitotic studies revealed that this species is a polyploid and with all probability a pentaploid with 2n = 5x = 55. This somatic chromosome number is being reported for the first time in Kaempferia galanga L. The karyotype was found to be a symmetric one and belonged to ‘1a’ group of Stebbins (1958) classification. Meiotic studies revealed the presence of associations involving three, four, five and six chromosomes in addition to the bivalents and univalent. However, the number of multivalents were much less than expected and later meiotic abnormalities were rather almost absent. Pollen grains also exhibited reasonable fertility and viability. Based on both mitotic and meiotic studies it was indicated that Kaempferia galanga L. is a segmental allopolyploid with five sets of genomes designated as A1A2A2A2A2. Studies on floral morphology and artificial pollinations to induce seed set led to the conclusion that seedlessness in the crop is mainly due to the incompatibility factors in the style and stigma. The spiny stigma does not permit the proper adherence and germination of the pollen grains and the pollen tube growth attained was not sufficient to surpass the lengthy style and to reach the ovary. Attempts to induce seed set by hand pollination and stub pollination also failed.
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    ThesisItemOpen Access
    Somatic embryogenesis in cocoa (Theobroma cacao L.)
    (Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1993) Jolly Antony; KAU; Achamma Oommen
    Investigation on somatic embryogenesis in cocoa (Theobroma cacao L.) were carried out at the college of Horticulture, Kerala Agricultural University, Vellanikkara during the period 1989-91, with the objective of studying the developmental potential of somatic embryos and its differentiation into plantlet by means of in vitro techniques. Stem and leaf segments, cotyledons and enbryonic axes of embryos collected from four typical genotypes of cocoa namely criollo, Amelonado, Amazon-forastero and Trinitario were used as explant. Cotyledons and embryonic axes of immature embryos (100 days pot anthesis) when incubated on MS basal semisolid medium supplemented with NAA 2 mg/1, thiamine 1 mg/1, casein hydrolysate 0.2 per cent (W/V) and coconut water 15 per cent (v/v) under dark for seven weeks resulted in high frequency and intensity of embryogenesis. Stem segements remined recalcitrant without embryoid regeneration, while leaf segments had a little potential. Auxins conditioned the culture for embryogenic competence while cytokinins had an inhibitory effect. The effect of NAA 2ppm was not replaceable by other auxins such as IAA, 2, 4-D. 2,4-D was a poor quantitative and qualitative stimulant of embryogenesis. Studies on auxincytokinin interaction revealed the counteracting effect of cytokinin on auxin. Fully mature embryoids germinated in hormone-free liquid medium consisting of half the salt concentration of MS and 5 per cent sucrose when incubated at 3000 lux (16 hours) for two weeks. De-cotyledonisation of embryoids and its rinsing with sterile distilled water and dessication, each for three minutes, enhanced the differentiation into plantlet. Shoot growth was stimulated by exogenous supply of NAA, GA3 and coconut water. In vitro rooting was promoted by reducing the salt concentration of MS medium to half strength and supplementing with IBA and activated charcoal. Germination and regeneration of embryoid into plantlet was dependent on its size. Sizes ranging from 0-4 mm were sub-optimal for germination and differentiation. Larger embroids (4-6 mm) had greater potential for differentiation. Quantitative and qualitative differnces were expressed by cocoa genotypes. Amelonado was found to be superior to Criollo and Amazon types for the induction of embryogenesis from cotyledons. Trinitario was the least efficient. Embryogenic potential of Amazon embryonic axes was superior to Criollo and Amelonado types. Trinitario embryonic axes remained recalcitrant. Plantlets were derived from embryoids within a time span of 13 weeks in Amelonado, Criollo and Amazon types.