Biochemical and molecular characterization of in vitro raised variants of Aloe vera
Loading...
Date
2014
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
YSPU
Abstract
The present investigation aims at “Biochemical and molecular characterization of in vitro raised
variants of Aloe vera”. Non Bitter and Bitter genotypes were found morphologically as well as biochemically
different. Regeneration from explants (leaf segment and shoot tip) of Non Bitter and Bitter genotypes was
carried out through indirect and direct method. Calli were initiated from leaf segment and shoots tip explants of Non Bitter genotype, while only shoot tip explant responded for callus induction in Bitter genotype.The best
media for callus induction was MS medium supplemented with 5.0 μM 2,4-D + 4.0 μM Kinetin + 25.0 μM
NAA. In Non Bitter genotype highest percentage of callus was obtained from shoot tip (86.11%) explants than
leaf segment (65.89%). In Bitter genotype only 30.89% callus induction was observed with shoot tip explant.
The calli thus obtained from shoot tip explants of Non Bitter and Bitter genotype did not show differentiation on MS medium supplemented with 5.0 μM BA + 1.0 μM IBA whereas 75.63% shoot bud regeneration was
observed from leaf derived calli of Non Bitter genotype. Direct adventitious shoot buds were induced from
shoot tip explants of both selected genotypes on MS medium supplemented with 8.0 μM BA + 1.0 μM NAA+
2.0 μM Kinetin. Solid MS medium supplemented with 7.5 μM BA + 10.0 μM Kinetin resulted in highest per
cent shoot multiplication of callus induced shoots as well as direct shoots of both genotypes. The callus induced shoots of Non Bitter genotype and direct shoots of both genotypes were rooted on 1/4th strength MS medium containing 0.04% activated charcoal. Shoots of both genotypes were treated with four doses (5, 10, 20, 40 Gy) of gamma irradiation and placed in Group 1 whereas, callus treated with four doses of gamma (5, 10, 20, 40 Gy), five concentrations of MMS (0.05%, 0.10%, 0.15%, 0.20%, 0.25%) and EMS (0.10%, 0.15%, 0.20%,0.25%,0.30%) was placed in Group 2. With the increase in dose/concentration of physical and chemical mutagen there found a decrease in survival percentage of shoots and callus. LD50 for treated shoots of Non Bitter and Bitter genotype was found close to 14.30 Gy and 11.25 Gy respectively, whereas LD50 of 9.0 Gy, 0.08% and 0.17% was observed for gamma, MMS and EMS treated callus of Non Bitter genotype. Morphologically, mutagenesis led to reduction in number and length of leaves in both plants of both Groups than control. Percent aloin content (estimated through HPLC) increased with the age of plants growing under natural conditions but remained same for all in vitro micropropagation stages. In group1, dendrograms derived on UPGMA clustering analysis using similarity coefficient of RAPD and ISSR markers separated selected variants of Bitter and Non Bitter genotypes into two separate clusters showing variation among two genotypes and selected variants. Similarly, dendrograms based on RAPD and ISSR analysis in Group 2 clustered gamma and chemical mutagen treated selected variants separately suggesting genetic variations among them.
Description
Keywords
aloe, planting, genotypes, biological phenomena, vegetative propagation, mutagens, selection, research methods, toxicity, regeneration