![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/KSEEB-Solutions.png\")
<\/p>\nQuestion 1.
\nExpand IBA.
\nAnswer:
\nIndole Butyric Acid.<\/p>\n
Question 2.
\nExpand NAA.
\nAnswer:
\nNaphthalene Acetic Acid.<\/p>\n
<\/p>\n
Question 3.
\nName the hormone which brings about inter nodal elongation?
\nAnswer:
\nGibberellin.<\/p>\n
Question 4.
\nWhich hormone is responsible for premature withering of fruits?
\nAnswer:
\nAbscissic acid.<\/p>\n
Question 5.
\nName the fruits ripening hormone.
\nAnswer:
\nEthylene.<\/p>\n
Question 6.
\nDefine vernalisation.
\nAnswer:
\nThe phenomenon of making the plants to flower by cold treatment followed by correct photoperiod is called vernalisation.<\/p>\n
<\/p>\n
Question 7.
\nWhat is bolting?
\nAnswer:
\nInternode elongation, and early flowering induced by gibberellins is called bolting.<\/p>\n
Question 8.
\nDefine growth.
\nAnswer:
\nGrowth can be defined as a permanent irreversible increase in size and volume of a cell, tissue, organ or organism accompanied by an increase in dry weight.<\/p>\n
Question 9.
\nWhat are the growing regions of the plant body?
\nAnswer:
\nThe meristematic regions or meristems are the growing regions of the plant body.<\/p>\n
Question 10.
\nMention the phases of growth.
\nAnswer:
\nThe phases of growth are.
\n(a) Cell division phase
\n(b) Cell elongation phase
\n(c) Cell maturation phase or differentiation phase.<\/p>\n
Question 11.
\nName the auxin which is used as a weedicide.
\nAnswer:
\n2,4-Dichlorophenoxy acetic acid.<\/p>\n
Question 12.
\nName the synthetic ethylene releasing compound used as a fruit ripener.
\nAnswer:
\nEthephon.<\/p>\n
<\/p>\n
Question 13.
\nWhich is commonly used as a selective weed killer?
\nAnswer:
\n2, 4 Dichlorophenoxy acetic acid.<\/p>\n
Question 14.
\nName the hormone responsible for bolting in biennials plants?
\nAnswer:
\nGibberellins<\/p>\n
Question 15.
\nName the hormone responsible for Richmond – lang effect in plants.
\nAnswer:
\nCytokinin<\/p>\n
Question 1.
\nExpand apical dominance?
\nAnswer:
\nWhen an apical bud is removed in a plant, the lower axillary buds grow rapidly, and the plant becomes profusely branched. If the apical bud is retained, the growth of the lateral bud is suppressed. This phenomenon is called apical dominance. Apical dominance is due to the high concentration of auxins at the apex.<\/p>\n
<\/p>\n
Question 2.
\nExplain the grand-period of growth.
\nAnswer:
\nThe second phase of growth in the growth curve is called the grand period of growth because in this phase, the growth is rapid due to the enlargement of newly formed young cells. This period of growth is known as log phase or exponential phase.<\/p>\n
Question 3.
\nExplain any two practical\/applications of auxins.
\nAnswer:
\nThe practical applications of auxins are:
\n(a) Auxins induce the rapid cell division, and cell elongation.
\n(b) Auxins are used in the prevention of premature withering of leaves, flowers and fruits.<\/p>\n
Question 4.
\nExplain any two functions of Gibberellins?
\nAnswer:
\nThe functions of gibberellins are:
\n(a) Gibberellins are helpful in the elongation of internodes in genetically dwarf plants.
\n(b) Gibberellins are used to break down the dormancy of seeds and buds.<\/p>\n
<\/p>\n
Question 5.
\nWhat are growth regulators? List any two applications of gibberellins.
\nAnswer:
\nGrowth regulators are organic substances produced naturally in minute quantities by highef plants in some particular cells, and are specifically transported to a target organ where they influence physiological functions. They can be either growth promoters or growth inhibitors.<\/p>\n
Applications of Gibberellins:
\n(a) Gibberellins are helpful in the elongation of internodes in genetically dwarf plants.
\n(b) Gibberellins are used to breakdown the dormancy of seeds, and buds.<\/p>\n
<\/p>\n
Question 6.
\nDraw a graph showing the typical growth curve and mark the phases of growth in it.
\nAnswer:<\/p>\n
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<\/p>\n
Question 7.
\nWrite any two applications of synthetic auxins.
\nAnswer:
\n(a) Synthetic Auxins like NAA or IBA is used in nurseries to induce adventitious roots by dipping the ends in a dilute solution.
\n(b) Synthetic 2, 4 – D is a selective weedicide, used to eradicate dicot weeds in monocot plantations.<\/p>\n
Question 8.
\nMention any two commercial applications of NAA.
\nAnswer:
\n(a) To produce parthenocarpic fruits like grapes, orange, tomato etc.
\n(b) To promote flowering of the entire crop at a time, in pineapple, cotton, maize etc.<\/p>\n
Question 9.
\nMention two physiological functions of abscissic acid.
\nAnswer:
\n(a) It is a powerful growth inhibitor and inhibits the growth by retarding cell division and cell elongation.
\n(b) It inhibits seed germination. It induces seed, and bud dormancy.<\/p>\n
<\/p>\n
Question 10.
\nWhy is abscisic acid also known as stress hormone?
\nAnswer:<\/p>\n
Question 11.
\n\u2018Both growth, and differentiation in higher plants are open\u2019. Comment.
\nAnswer:
\nGrowth, and development in higher plants is referred to as being open because various meristems, having the capacity for continuously dividing and producing new cells, are present at different locations in these plant bodies.<\/p>\n
Question 12.
\nWould a defoliated plant respond to photoperiodic cycle? Why?
\nAnswer:
\nNo. as it cannot perceive light, it cannot respond to photoperiodic cycle.<\/p>\n
Question 13.
\nWhat is vernalization? How does this help in cultivation of winter variety of wheat?
\nAnswer:
\nBesides correct photoperiod, some plants require low temperature treatment for flowering. This treatment is known as vernalization.<\/p>\n
Vernalization prevents precocious reproductive development late in the growing season, and enables the plant to have sufficient time to reach maturity.<\/p>\n
<\/p>\n
Certain food plants like wheat, barley and\u00a0 have two varieties called,<\/p>\n
The spring variety is planted in spring, and it completes the lifecycle before the growing season. The winter variety is normally planted in autumn or spring and is harvested by mid-summer.<\/p>\n
Question 1.
\nDescribe briefly:
\n(a) Arithmetic growth.
\n(b) Geometric growth.
\n(c) Sigmoid growth curve.
\n(d) Absolute and relative growth rates.
\nAnswer:
\n(a) Arithmetic growth\u00a0refers to the situation where a population increases by a constant number of persons (or other objects) in each period being analysed.<\/p>\n
<\/p>\n
(b) Growth Rate:
\nThe increase in growth per unit time is termed as growth rate. Rate of growth may be arithmetic or geometric. In arithmetic growth, one of the daughter cells formed by mitosis continues to divide, while the other undergoes differentiation and maturation. In Geometrical growth, both the daughter cells formed after mitosis, retain the in ability to divide.<\/p>\n
(c)<\/p>\n
(d) The measurement of total growth per unit time and its comparison is known as absolute growth while the growth of a particular system per unit time is called relative growth rate, it is expressed on a common basis.<\/p>\n
<\/p>\n
Question 2.
\nWhat do you understand by photoperiodism and vernalisation? Describe their significance.
\nAnswer:
\nPhotoperiodism :
\nPlants, in order to flower, require a particular day length or light period called photoperiod and response of the plants to photoperiod in terms of flowering is called photoperiodism. Photoperiodism was first studied by W.W. Garner, and H.A. Allard.<\/p>\n
Based on their photoperiodic responses, plants are classified into the following groups:
\n(1) Long Day Plants: These flower in photoperiod more than critical day length, eg : Wheat, oats etc.
\n(2) Short Day Plants: These flower in photoperiod less than critical day length. e.g: Tobacco, Chrysanthemums etc.
\n(3) Day Neutral Plants: These are the plants which are not influenced by the duration of light for their flowering. e.g: Tomato, cucumber, cotton etc.<\/p>\n
Vernalisation :
\nBesides correct photoperiod, some plants require low temperature treatment for flowering. This treatment is known as vernalization.<\/p>\n
Vernalization prevents precocious reproductive development late in the growing season, and enables the plant to have sufficient time to reach maturity.<\/p>\n
Certain food plants like wheat, barley and rye have two varieties called,
\n(i) Spring variety, and
\n(ii) Winter variety.
\nThe spring variety is planted in spring, and it completes the lifecycle before the growing season. The winter variety is normally planted in autumn or spring and is harvested by mid-summer.<\/p>\n
<\/p>\n
Question 3. Question 4. Dedifferentiation: Permanent cells like parenchyma can revert back to meristematic activities (cell division) to form secondary meristern. This conversion is called Dedifferentiation.<\/p>\n Redifferentiation: If the secondary meristem divides to produce new cells, which further differentiate to form micelle cells, and once again lose the capacity to divide, then it is called as Redifferentiation.<\/p>\n Question 1. Dedifferentiation : Permanent cells like parenchyma can revert back to meristematic activities (cell division) to form secondary meristetn. This conversion is called Dedifferentiation.<\/p>\n Redifferentiation: If the secondary meristem divides to produce new cells, which further differentiate to form micelle cells, and once again lose the capacity to divide, then it is called as Redifferentiation.<\/p>\n Question 2. Question\u00a0 3. (b) quickly ripen a fruit. (c) delay leaf senescence. (d) induce growth in axillary buds. (e) \u2018bolt\u2019 a rosette plant. (f) induce immediate stomatal closure in leaves. Question 4. Based on their photoperiodic responses, plants are classified into the following groups:<\/p>\n Vernalisation : Vernalization prevents precocious reproductive development late in the growing season, and enables the plant to have sufficient time to reach maturity.<\/p>\n Certain food plants like wheat, barley and\u00a0 have two varieties called,<\/p>\n The spring variety is planted in spring, and it completes the lifecycle before the growing season. The winter variety is normally planted in autumn or spring and is harvested by mid-summer.<\/p>\n Growth<\/p>\n Measurement of Growth: Growth is measured as increase in : Growth Rate:<\/p>\n Conditions for Growth:<\/p>\n Phases of Growth: Growth Curve: (2) Log phase In this phase, the rate of growth is very rapid. The plant shows high rate of growth, and reaches maximum height. Hence this phase is called exponential phase or grand period of growth.<\/p>\n (3) Steady phase or stationary phase This is the last phase in which plants shows no growth. Therefore the growth curve becomes almost horizontal.<\/p>\n Development :<\/p>\n Differentiation, Dedifferentiation and Redifferentiation:<\/p>\n Growth Regulators \/ Hormones<\/p>\n I. Natural Growth Substances: Auxins:<\/p>\n Gibberellins:<\/p>\n Cytokinins \/ Kinetins<\/p>\n Abscisic Acid \/ Aba \/ Dormin<\/p>\n Ethylene<\/p>\n Photoperiodism : Vernalisation : Certain food plants like wheat, barley and have two varieties called, Karnataka 1st PUC Biology Question Bank Chapter 15 Plant Growth and Development 1st PUC Biology Plant Growth and Development One Marks Questions and Answers Question 1. Expand IBA. Answer: Indole Butyric Acid. Question 2. Expand NAA. Answer: Naphthalene Acetic Acid. Question 3. Name the hormone which brings about inter nodal elongation? Answer: Gibberellin. Question 4. …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88273"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=88273"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88273\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=88273"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=88273"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=88273"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nWhat would be expected to happen if:
\n(a) GA3<\/span><\/sub><\/span> is applied to rice seedlings.
\n(b) Dividing cells stop differentiating.
\n(c) A rotten fruit gets mixed with unripe fruits.
\nAnswer:
\n(a) Will exhibit intemode elongation and increase in height.
\n(b) If dividing cells stop differentiating, mass of undifferentiated cells is formed called callus.
\n(c) If a rotten fruit gets mixed with unripe fruits, then the ethylene produced from the rotten fruits will hasten the ripening of the unripe fruits.<\/p>\n
\nWith reference to growth, define the following terms.
\n1. Differentiation.
\n2. Dedifferentiation.
\n3. Redifferentiation
\nAnswer:
\nDifferentiation, Dedifferentiation and Redifferentiation:
\nDifferentiation: It is the conversion (maturation) of meristematic cells, to regain the power to divide under certain conditions.<\/p>\n<\/p>\n1st PUC Biology Plant Growth and Development Five Marks Questions and Answers<\/h3>\n
\nDefine growth, differentiation development, dedifferentiation, redifferentiation, determinate growth, meristem, and growth rate.
\nAnswer:
\nDifferentiation: It is the conversi\u00f3n (maturation) of meristematic cells, to regain the power to divide under certain conditions.<\/p>\n<\/p>\n
\nList five main groups of natural plant growth regulators. Write a note on discovery, physiological functions and agricultural\/horticultural applications of anyone of them.
\nAnswer:<\/p>\n\n
\nWhich one of the plant growth regulators would you use if you are asked to:
\n(a) induce rooting in a twig.
\nAnswer:
\nAuxin.<\/p>\n
\nAnswer:
\nEthylene.<\/p>\n
\nAnswer:
\nCytokinin.<\/p>\n<\/p>\n
\nAnswer:
\nCytokinin.<\/p>\n
\nAnswer:
\nGibberellin.<\/p>\n
\nAnswer:
\nAbscisic acid (ABA).<\/p>\n
\nDefine photoperiodism and vernalisation. Describe their significances.
\nAnswer:
\nPhotoperiodism :
\nPlants, in order to flower, require a particular day length or light period called photoperiod and response of the plants to photoperiod in terms of flowering is called photoperiodism. Photoperiodism was first studied by W.W. Garner, and H.A. Allard.<\/p>\n\n
\nBesides correct photoperiod, some plants require low temperature treatment for flowering. This treatment is known as vernalization.<\/p>\n<\/p>\n\n
1st PUC Biology Plant Growth and Development Text Book Questions and Answers<\/h3>\n
\n
\nGrowth at the cellular level is mainly due to the increase in the amount of protoplasm. Since , it is difficult to measure the increase in protoplasm, one measures some quantity which is proportional to protoplasmic increase.<\/p>\n<\/p>\n
\nFresh weight, dry weight, length or area, volume \/ size and cell number.<\/p>\n\n
\n
\nGrowth occurs in meristems. A meristematic cell passes through three phases or stages which are as follows.<\/p>\n\n
\nThe curve obtained when the growth in size or weight or on entire plant or its individual parts is plotted against time is called growth curve. It is always \u2018S\u2019 or sigmoid in shape.
\nIt shows three distinct phases namely.
\n(1) Lag phase.
\n(2) Log phase.
\n(3) Steady phase.
\n(1) Lag phase This is the initial stage where the growth rate is very slow. But it gradually increases with the time.<\/p>\n<\/p>\n\n
\n
\n
\nThese are naturally occurring in the plant body. They are of two types, namely:-
\n1. Growth Promoters :- Which promote growth e.g. Auxins, Gibberellins and Cytokinins.
\n2. Growth Retarders :- Which retard growth e.g. Ethylene and Abscissic Acid.<\/p>\n<\/p>\n\n
\n
\n
\n
<\/p>\n\n
\nPlants, in order to flower, require a particular day length or light period called photoperiod and response of the plants to photoperiod in terms of flowering is called photoperiodism. Photoperiodism was first studied by W.W. Garner, and H.A. Allard.
\nBased on their photoperiodic responses, plants are classified into the following groups:<\/p>\n\n
\ne.g: Tobacco, Chrysanthemums etc.<\/li>\n
\nBesides correct photoperiod, some plants require low temperature treatment for flowering. This treatment is known as vernalization.
\nVernalization prevents precocious reproductive development late in the growing season, and enables the plant to have sufficient time to reach maturity.<\/p>\n<\/p>\n
\n(i) Spring variety, and
\n(ii) Winter variety.
\nThe spring variety is planted in spring, and it completes the lifecycle before the growing season. The winter variety is normally planted in autumn or spring and is harvested by mid-summer<\/p>\n1st PUC Biology Question Bank with Answers<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"