Jumat, 22 Februari 2013

Development from Flower to Seed



Flower bud initiation, growth to maturity

Within a species flowering time often varies according to location.  Also within a given population differences can be found between individuals.  Flowering habits are strongly genetically controlled.

Time from formation of flower bud to mature seeds may take from a few months to 3 years.

Flowering habits vary with latitude.  In the temperate zones, bud initiation happens in the year before flowering, and 2-3 years to mature fruit/seed is normal.  In the tropical zone short intervals of less than 6 months from initiation to maturity are typical.

The warmer conditions of lowland tropics may result in the earlier ripening (altitude effect).  Conifers take generally longer time to make mature seed than hardwoods. 
In many tropical hardwoos, flower buds develop within a short period of time. 

 In Tectona grandis, for example, they can not be seen easily until shortly before the flower open.  A flower opens in the morning between 7 and 9, the pollen on the anthers start to appear between 9 and 10, and the stigma is receptive from 10 in the morning till around 2 o’clock in the afternoon. 

 If no pollination occurs, the whole flower falls off during the coming days.  Fruit development lasts for 4 months after which time the fruits are of full size.  It takes still another 1-2 months for seed to mature. 

 In Gmelina arborea the flower buds can be identified some 10 days before the flower opens, and mature fruits are found after about 2 months.


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