These MP Board Class 11th Biology Notes for Chapter 15 Plant Growth and Development help students to get a brief overview of all the concepts.
MP Board Class 11th Biology Notes Chapter 15 Plant Growth and Development
→ Growth is the permanent change in size and increase in dry weight.
→ Growth is measured by Auxanometer.
→ F. W. Went (1928) discovered the auxins and perform Avena coleoptile test for the bioassay of auxins.
→ Kogl and Haagen Smit (1931) isolated auxin-a (auxentriolic acid, C18H32O5) from human urine.
→ Auxin-b (auxenolinic acid, C18H30O4) was isolated by Kogl, Erxleben and Haagen Smit from com germ oil.
→ Heteroauxin (Indole-3 acetic acid, C10H9O2N) was isolated from human urine.
→ Auxin initiates and promote cell division in cambium cells (play important role in secondary growth).
→ Auxin prevents premature leaf fall by arresting the formation of abscission layer.
→ Auxin is useful in tissue culture experiments and callus formation.
→ Indolebutyric acid (IBA) is used to induce foot formation in cuttings.
→ Auxin is used to induce parthenocarpy in Tomato, Apples, Cucumbers and other plants.
→ 2,4-D (2,4-Dichlorophenoxyacetic acid) is a synthetic auxin which is used in eradication of weeds (Herbicide or Weedicide).
→ Gibberellin was discovered by Kurosawa (1929), a Japanese.
→ IAA is the principal naturally occurring auxin of all higher plants.
→ The term auxin was coined by Kogl and Haagen Smit (1933). It is a Greek word derived from ‘auxin’ which means to grow.
→ The term hormone was used for the first time by Beylis and Starling (1904).
→ Foolish seedling disease of paddy is caused by a fungus Gibberella fujikuroi which is now known as Fusarium heterosporum.
→ Intemodal elongation is caused by gibberellins.
→ Yabuta and Sumiki isolated the gibberellin for the first time from fungus Gibberella fujikuroi.
→ Gibberellin is used for the elongation of genetically dwarf plants.
→ Gibberellins can substitute low temperature treatments (Vernalization) and long day treatments.
→ Cytokinins are hormones that induce cell division by inducing cytokinesis.
→ Ethylene is a volatile gas present in atmosphere as a component of smoke and other industrial gases.
→ According to Denny (1924), ethylene gas is highly effective in inducing fruit ripening.
→ Degradation of proteins can be prevented by application of cytokinin.
→ Miller et al isolated cytokine from yeast DNA for the first time.
→ Fruits can be made to ripe artificially by treating them with ethylene.
→ Abscisic acid is a powerful growth inhibitor.
→ Cams and Addicott (1963) discovered that Abscisin-II is responsible for shedding of cotton balls.
→ According to Wareing and Cornforth, ‘dormin’ induces bud dormancy.
→ ABA induces leaf abscission.
→ The term photoperiodism was coined by Garner and Allard (1920) to designate the response of organisms to the relative length of the day and night and the term photoperiod to designate the favourable length of day for each plant.
→ Pigment responsible for flowering, seed germination and leaf development is phytochrome.
→ ABA inhibits GA stimulated growth.
→ Lysenko (1938) used the term ‘vernalization’ for low temperature promotion of flowering in plants.
→ Vernalization is a method of inducing early flowering in plants by pretreatment of their seeds at very low temperature.
→ Florigen is the hormone which causes flowering.
→ Vernalin is a hormone which induces flowering after low temperature treatment.
→ Growth shows a characteristic S-shaped growth curve.
→ The growth and development of plants are regulated by many factors.
→ Growth regulators of phytohormones vary chemically and also differ in their specific biological actions.
→ Auxins, gibberellins, cytokinins, abscisic acid and ethylene are the main hormonal substances synthesized in the plants.
→ Photoperiodism has a marked influence on the behaviour of plants particularly flowering and plants are categorized into long day, short day and day neutral plants.
→ Phytochromes are the photoreceptive forms of two kinds : PR and PFR.