EFFECT OF SHADE ON LEAF AND CELL-SIZE AND NUMBER OF EPIDERMAL-CELLS IN GARLIC (ALLIUM-SATIVUM)

Garlic cultivars 'Bangladesh Local' and 'Fructidor' were grown under field conditions in the south-east of England and subjected to different shading treatments. The effects of shading on final leaf size were related to cell numbers and dimensions. An increase in light intensity reduced leaf length and size of epidermal cells. In the cv. Fructidor, cell length was reduced, but in the cv. Bangladesh Local, both length and width of cells were reduced. The stomatal index decreased with increasing light intensity in both cultivars. Leaf thickness increased with light intensity, resulting in corresponding gains in leaf d. wt per unit area.Data from cv. Fructidor growing in full sunlight indicated that the epidermal tissue adjacent to the abaxial leaf surface had a greater number of cells than that next to the adaxial surface, but no significant differences were found in the corresponding cell depths. The size of epidermal cells in both epidermises decreased from the base to tip of the leaf due to reduction in cell length and width. The influences of environmental factors on leaf growth in general, and those related to shade, are also discussed. © 1991 Annals of Botany Company.