question_answer

The chemical nature of gibberellins is that they are:

A)  acidic          

B)  alkaline

C)  proteinaceous

D)  amines

Correct Answer: A

Solution :

Gibberellins (Yabuta, 1935) are weakly acidic plant  growth hormones having gibbane ring structure which cause cell elongation of intact plants in general and increased incemodal length of genetically dwarfed plants (Pea, corn) in particular. There are more than 100 gibberellins reported from widely different organisms, and are devoted as \[G{{A}_{1}},G{{A}_{2}},G{{A}_{3}}\]and so on. Gibberellic acid \[(G{{A}_{3}})\]was one of the first gibberellins to be discovered and remains the most widely 5 fudied form. Gibberellins find many uses in agriculture, horticulture and floricultrue. They increase number and size of several fruits such as grapes and tomato. They enhance shape and size of apple. They induce production of seedless pomaceous fruits through partheno corpy. They increase yield of malt from barley grains. They delay ripening of fruits, which extends period of marketing as well as, their storage. They are used to induce off season flowering in many long day plants, as well as plants requiring vernalization. They increase yield ofsugarcane crop by increasing length of stem. In juvenile conifers, they hasten maturity period. They also promote bolting in bet cabbages and many plants with rosette habits.