The term SDP stands for Short-day plants. Short day plants require a relatively short daylight period (about 8 to 10 hours) and a continuous dark period of about 14-16 hours for subsequent flowering. One example of a short-day plant is Nicotiana tabacum . In a short-day plant, if the dark period is interrupted with brief exposure to red light, the flowering will not occur.

DNP expands as Day Neutral plant. Depending upon the duration of photoperiod, plants are classified into three categories, such as short-day plants (SDP), long-day plants, and day-neutral plants. The day-neutral plant flowers irrespective of the length of the period of light it is exposed. Two examples of day-neutral plants are Cucumis sativu s and Helianthus annuus .

GA stands for gibberellic acid. It is a plant hormone that was isolated from the fungus , Gibberella fujikuroi in crystalline form while working in the rice fields. The most significant effect of gibberellic acid is that it induces reversal of dwarfism in genetically dwarf plants such as corn, pea, sugarbeet, etc. Studies indicate that the dwarf plants have a very low GA level, thus the external application of GA to genetically dwarf plants induces rapid elongation growth.

ABA stands for abscisic acid is a growth inhibitor substance found in some plant. It is an active substance causing abscission of different parts of plants like leaves, fruits, etc. It promotes senescence of leaves. Flowering in long day plants are inhibited by ABA but flowering in short day plants are stimulated by ABA. It acts as an antitranspirant because it causes partial closure of stomata under drought.

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TRUEMAN'S ELEMENTARY BIOLOGY VOL. I For XI Class of 10+2>Plant Physiology>Chapter 19 - Plant Growth and Development>TEST QUESTIONS

K N Bhatia and M P Tyagi Solutions for Exercise 1: TEST QUESTIONS

Author:K N Bhatia & M P Tyagi

K N Bhatia Biology Solutions for Exercise - K N Bhatia and M P Tyagi Solutions for Exercise 1: TEST QUESTIONS

Attempt the free practice questions from Exercise 1: TEST QUESTIONS with hints and solutions to strengthen your understanding. TRUEMAN'S ELEMENTARY BIOLOGY VOL. I For XI Class of 10+2 solutions are prepared by Experienced Embibe Experts.