36 public questions tagged with this topic.
Meristem tissues are used in tissue culture to produce virus-free plants as they are usually not infected by viruses. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function, Topic: Structural organization and physiology.
Suspension cultures differ from callus grown on agar by continuous agitation ensuring homogeneous nutrient and gas distribution and removal of growth inhibitors. Inoculation of friable callus fragments into Erlenmeyer flasks on orbital shaker at 110 rpm disperses cells, creates single cells and small aggregates suitable for growth kinetic measurements, mutant selection, and bioreactor scale-up. Uniform cell size allows precise biomass estimation by packed cell volume and dry weight, enabling process control for large-scale production of cells for biochemical studies, somatic embryogenesis, art
Ref: Murashige & Skoog 1962 suspension; Street 1977 suspension methods; NCBI NBK26844 large scale; Phillips Plant Cell Culture 2010 bioreactor.
Somatic embryos undergo organized morphogenetic sequence resembling zygotic embryos but initiating from somatic cells without fertilization. First division produces isodiametric globular mass with outer protoderm and inner ground meristem, establishing radial polarity driven by polar auxin transport via PIN proteins. Bilateral symmetry emerges when cotyledon primordia initiation regulated by HD-ZIP transcription factors creates heart stage, defining shoot apical meristem and hypocotyl. Subsequent elongation along apical-basal axis expands procambium and root pole, forming torpedo stage charact
Ref: Zimmerman Plant Physiol 1993 somatic embryogenesis; Taiz & Zeiger Ch 16 patterning; NCBI NBK215584 WUSCHEL-PIN; Bhojwani Ch 5 stages globular heart torpedo.
Plant cell walls composed of cellulose microfibrils embedded in hemicellulose and pectin matrix prevent direct membrane manipulation. Protoplast technology demands complete wall removal without lysing protoplasm. Cellulase complex from Trichoderma reesei hydrolyzes β-1,4 glycosidic bonds of cellulose, while pectinase or macerozyme from Rhizopus degrades polygalacturonate of middle lamella, loosening intercellular adhesion. Digestion carried out in isoosmotic solution of mannitol or sorbitol at pH 5.4 to 5.8, supplemented with calcium chloride for membrane stabilization, releases spherical prot
Ref: Cocking 1960 protoplast isolation; Bhojwani & Dantu Ch 14 enzymatic; NCBI PMC3248752 cellulase macerozyme protocol; Gamborg & Phillips Methods.
Genetic analysis distinguishes traits by inheritance pattern. Qualitative characters show distinct phenotypic classes, typically governed by one or few major genes with dominant recessive interaction and minimal environmental modulation. In tissue culture derived plants, discrete changes like flower color alteration, presence or absence of awns, variegation, leaf margin serration, or shifts in flowering date and leaf size that occur as recognizable categories illustrate this mode. Scoring involves visual classification rather than measurement, with Mendelian segregation in selfed progenies. Su
Ref: Campbell Biology 12th Ch 14 qualitative traits Mendelian; NCBI NBK11556 monogenic markers; Alberts Ch 8; Poehlman Breeding qualitative descriptors; https://www.ncbi.nlm.nih.gov/books/NBK218342/
Plant growth regulators drive developmental plasticity in vitro, and prolonged exposure creates reversible adaptive responses rather than permanent DNA changes. High levels of synthetic auxins like 2,4-D and cytokinins such as BAP increase endogenous hormone synthesis, alter receptor sensitivity, and remodel chromatin through changes in DNA methylation and histone acetylation. Cells become habituated, growing without external hormones, show vitrification with water-soaked translucent appearance, or lose morphogenetic competence. Such phenotypes affect culture behavior, shoot regeneration frequ
Ref: Alberts Molecular Biology of Cell 6th ed Ch 21 Plant tissue culture; NCERT Biology XII Unit 9; NCBI Bookshelf NBK218342 somaclonal variation physiology and habituation.
Somaclonal variation is classified into genotypic and phenotypic categories based on nature of change and heritability, distinction crucial for breeding applications. Genotypic variation involves stable heritable alterations in DNA sequence or chromosome constitution transmitted through meiosis to sexual progeny and persisting after repeated vegetative propagation. Examples include nucleotide substitutions insertions deletions caused by replication errors oxidative damage, activation of transposable elements causing insertional mutagenesis, large scale changes aneuploidy polyploidy translocati
Ref: Evans & Sharp 1986 classification; Bajaj 1990 genotypic vs phenotypic somaclonal.
Somaclonal variation denotes phenotypic and genetic variability observed among plants regenerated from somatic cells in tissue culture, term introduced by Larkin and Scowcroft 1981 to describe variation in clones derived from same explant. Unlike seed derived variation, somaclonal variation originates from stress imposed by in vitro environment high concentrations of synthetic auxins especially 2,4-D, rapid cell cycles, oxidative burst from autoclaved medium components, and epigenetic reprogramming during dedifferentiation redifferentiation. Underlying mechanisms include point mutations due to
Ref: Larkin & Scowcroft 1981 somaclonal variation; NCBI Plants review somaclonal.
Protoplasts are plant cells that completely lack cell wall, defined as protoplasm enclosed only by plasma membrane after removal of cellulose hemicellulose and pectin components. Isolation employs enzyme mixture cellulase hydrolyzing beta 1,4 glucan backbone of cellulose microfibrils and pectinase macerozyme dissolving middle lamella pectin crosslinking cells, often adding hemicellulase driselase; incubation performed in osmoticum mannitol sorbitol 0.4-0.6 molar to prevent lysis due to loss of wall counteracting turgor. After digestion spherical protoplasts released from leaf mesophyll or cell
Ref: Cocking 1960 protoplast isolation; NCBI Bookshelf protoplast manual.
Somatic hybridization involves fusion of protoplasts isolated from somatic vegetative tissues of different species cultivars or genera, bypassing sexual incompatibility barriers that prevent conventional crossing due to pre zygotic pollen stigma incongruence or post zygotic endosperm abortion. Protoplasts are obtained by enzymatic digestion of cell walls using cellulase Onozuka R-10 and macerozyme releasing naked cells bounded solely by plasma membrane maintaining totipotency to regenerate wall and divide. Mixed protoplast populations labeled with different fluorescent markers or selectable co
Ref: Gleba & Sytnik 1984 somatic hybridization; Evans et al., Handbook Plant Cell Culture.
Gynogenesis differs from androgenesis because it uses female gametophyte components unfertilized ovules ovaries or embryo sacs as explant source rather than anther pollen. In gynogenesis egg cell synergid or antipodal cells within embryo sac are induced to develop sporophytically into haploid embryo without fertilization, typically by culturing unpollinated ovaries or ovules on sucrose enriched medium with auxin cytokinin combination. Female gametophyte origin ensures captured genome is that of maternal parent, contrasting with androgenesis capturing paternal genome from microspores. Gynogenes
Ref: Yang & Zhou Theor Appl Genet gynogenesis; Bohanec 2009 haploid production review.
Murashige and Skoog medium proposed in 1962 for tobacco pith culture remains gold standard and most widely used basal medium for plant tissue culture due to broad applicability and high salt formulation supporting rapid growth across herbaceous and many woody species. Its composition features high concentrations of macronutrients ammonium nitrate 1650 mg per L and potassium nitrate 1900 mg per L providing dual nitrogen source favoring both amino acid synthesis and pH buffering, plus calcium chloride, magnesium sulfate, potassium dihydrogen phosphate; chelated iron as Fe-EDTA, micronutrients ma
Ref: Murashige & Skoog Physiol Plant 1962; NCBI NBK26873 MS medium composition.
