the Role of light and temperature in growth and development regulation. Formation and growth of reserving bodies

you are: the Role of light and temperature in growth and development regulation

Some agricultural plants and decorative kinds make multiple copies by means of reserving bodies. One of known examples - the tuber of a potato representing expansion of a stalk. Klubneobrazovaniju cool nights and short days though different grades differ on reaction to these factors or on requirement for them promote. The length of day is perceived by leaves; then any hormonal influence which yet has been not quite found out, brakes growth (by a stretching) a tip of a horizontal stalk (stolona), causing thereby its transformation into a tuber. There is data in favour of that formation of tubers can be promoted by quantity increase abstsizovoj acids and tsitokininov.

The Bulbs formed after flowering from the expanded bases of leaves, surrounding not extended tip of a stalk, before germination pass a dormant period. The skilful reference with cultures forming bulb, such as tulips, has created base of the important gardening industry in the Netherlands. As the key factor the temperature here serves. Cool summer nights promote moving of the carbohydrates synthesised in green leaves (source), to a developing kidney (consumer) (see gl. 8). After dying off of leaves it is formed primordy kidneys for tsvetkov the next year. Heats are favorable for this stage in the late summer or in a storage time more. Then the period with low temperature is necessary (jarovizatsija, see gl. 12) before the pedicel stretching will begin. It usually occurs during winter time, but bulbs it is possible to force to blossom indoors in the winter, having subjected to their influence of heats (20 °s) within 4-6 weeks, and then temperatures 5-9°С within approximately 6 weeks. After that carrying over to heat conducts to fast growth and flowering.

At biannual root crops, such as a sugar beet, formation of a reserving root crop occurs in the first year of vegetation; then for plants it is necessary holodovaja jarovizatsija before flowering the next summer but if culture grow up for the sake of sugar cleaning make in the first autumn.

Than more long the vegetative period in the first summer and the earlier is formed a full sheet cover, the above a crop. However, if seeds vysejat too early, sprouts can jarovizirovatsja, and in this case tsvetki appear during the first season, and root crops are not formed. Therefore crops time has crucial importance. position has a little improved as a result of deducing of grades (especially sugar beet), demanding for jarovizatsii the long cold period; seeds of such grades can be sowed in the spring, and they will not be jarovizirovatsja.