Question

Bolting means
A) Elongation of stem in rosette plants
B) Dwarfing of stem
C) Increase in flowering
D) Appearance of flowers

Answer 1

Hint: Bolting is the term applied to vegetable crops when they prematurely run to seed, usually making them unusable. A cold spell or changes in day length initiates this behaviour. It can affect a wide range of vegetables including lettuce, spinach and fennel.

Complete answer:
Gibberellins are weakly acidic growth hormones having gibane ring structure which causes cell elongation of intact plants. In general, an increase internodal length of genetically dwarf plants eg. Pea corn etc. Gibberellins induce subapical meristem to develop faster. This causes the elongation of reduced stem or bolting in case of rosette plant. Eg. Henbane, cabbage and root crops eg. Raddish.

So therefore from an agricultural point of view some crops are very important but they are somehow unusable because of their short height and length. By doing bolting i.e elongation of the stem in specially the rosette plants we can improve our yield. The answer is elongation of the stem in rosette plants.

Note: A weekly dose of 0.1mg gibberellic acid made cabbage plants grow taller than 3.5 metre. Normally bolting occurs at the onset of the reproductive phase, it is favoured in nature by either cold nights or long days.

Other uses of gibberellin:
>Increase the number and size of several fruits.
>It increases the yield of malt from barley grains.

Seedless pomaceous fruits can be produced by application of gibberellins to unpollinated flowers.
Delays senescence so that fruit can be left on the tree for a longer period. It extends the period of marketing. Ripening of citrus fruits can be delayed with the help of gibberellins. This is useful in storing fruits. It can be used in inducing offseason flowering In many long day plants as well as plants requiring vernalisation.