Factors affecting transpiration

1.Development of morphological characters:

Transpiration differs with the age of the organ/organism. Because of high surface to volume ratio, new leaves loss more water. The smaller the commodity the larger the surface area to volume ratio. Leaves have two surfaces so they have a larger surface area to volume ratio than fruits. The greater its surface area to volume ratio, the faster the diffusion of gases involved in respiration, exit of water through transpiration and entry of microorganism or chemicals. In general therefore the greater the surface area to volume ratio, the shorter the post harvest life.

Ex. Vegetable                          Weight loss (%) day

Asparagus                                          8.4

Snap bean                                           4.0

Carrot (top removed)                        3.6

Cucumber                                          2.5

Tomato                                              0.9

Asparagus: The weight loss is because, the shoots are new growing portion, tissue is physiologically very active and the surface to volume ratio also high.

Snap bean: Beans are physiologically not mature, cuticular layers is very thin and less waxy and surface to volume ratio is high.

Carrot: Root has no stomata, thin epidermal tissue and presence of lenticels. Removal of foliage causes reduction in surface to volume ratio.

Cucumber: Outer layer protective tissue is highly lignified, Physiologically matured as compared to above commodities.