215 public questions tagged with this topic.
Auxins and cytokinins synergistically promote ll division and enlargement, especially in tissue culture. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
Photorespiration involves three organelles: chloroplast, peroxisome, and mitochondrion. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
Ethylene is known to promote, not delay, fruit ripening, especially in climacteric fruits. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Biology - Botany portion covering relevant concept, Topic: Plant structure, physiology and applications.
NADPH provides reducing power to convert carbon dioxide into glucose in the Calvin cycle. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.
Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Botany section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Botany portion (Latest NCERT Textbooks for Academic Session 2026-27 -
Napiform roots, such as those found in turnip, store food and appear swollen with a tapering end. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Biology - Botany portion covering relevant concept, Topic: Plant structure, physiology and applications.
Endodermal lls contain Casparian strips, which regulate the selective movement of water and minerals into the vascular tissue. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Biology - Botany portion covering relevant concept, Topic: Plant structure, physiology and applications.
Câ‚„ plants have high water-use efficiency due to their ability to minimize photorespiration. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
Biochemical variation reflects lesions in primary and secondary metabolic pathways rather than chromosome morphology. In heterotrophic tissue culture, selection pressure for photolithotrophy is relaxed, allowing chlorophyll deficient sectors, carotenoid-less callus, or mutants defective in Calvin cycle enzymes Rubisco, phosphoribulokinase, and glyceraldehyde-3-phosphate dehydrogenase to proliferate. Altered carbon metabolism impairs sucrose independence, starch synthesis, or nitrogen assimilation via nitrate reductase and glutamine synthetase deficiency. Such lines require exogenous vitamins, amino acids, or organic acids for survival and turn chlorotic upon transfer to photoautotrophic conditions. Detection uses pigmentation scoring, gas exchange measurement, and enzyme assays. Because defect maps to enzymatic machinery producing sugars and precursors, rather than hormone response or karyotype, it exemplifies biochemical cause of somaclonal variation, often non-revertible without genetic complementation and important when screening for photosynthetic competence of regenerants. Enzymatic assays for Rubisco and chlorophyll fluorescence quantification confirm biochemical deficiency. Unlike reversible habituation, these variants often need genetic complementation or medium supplementation, illustrating how relaxed photoautotrophic selection in tissue culture unmasks metabolic lesions that compromise carbon fixation efficiency in regenerants.
Ref: Taiz & Zeiger Plant Physiology 6th ed Ch 7 photosynthesis; NCBI NBK215354 carbon metabolism; Campbell Biology 12th Ch 10 auxotrophs; Bhojwani Plant Tissue Culture biochemical variation.
Late ripening grapes undergo water loss and sugar concentration contributing to raisin formation and wine quality concentration. Berry pericarp consists of epidermal cells covered by waxy cuticle containing embedded aquaporins of PIP1, PIP2 and TIP families forming selective water pores. Water loss process involves evaporation from skin surface lowering apoplastic water potential creating gradient that draws cellular water outward. Movement across plasma membrane and tonoplast occurs via facilitated diffusion through aquaporin pores functioning as channels allowing single file diffusion at billion molecules per second down water potential without ATP coupling or conformational shuttling distinct from simple lipid diffusion alone. Although osmosis term commonly used at tissue level, molecular mechanism qualifies as facilitated diffusion because protein accelerates polar molecule traversing hydrophobic core. Reverse osmosis requires applied hydrostatic pressure exceeding osmotic pressure to force water opposite natural direction, not relevant here. Active transport requiring ion gradients or ATP would transport solutes uphill, not observed. Ion channels for sodium or potassium selective do not transport substantial water. Therefore facilitated diffusion via aquaporins drives berry shriveling water loss.
Ref: Koch, Plant Cell Biology, Aquaporin-Mediated Facilitated Diffusion in Grape Berry Shriveling.
Abscisic acid (ABA) is a stress hormone that induces stomatal closure to reduce water loss during drought. It promotes dormancy, not germination.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Gibberellins stimulate the production of enzymes like alpha-amylase, which breaks down starch during seed germination. Water, temperature, and oxygen are essential for germination.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
The lag phase is the initial phase with slow growth, preparing cells for rapid division in the log phase.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
