STOMATAL DENSITY AND INDEX IN LEAVES OF THREE RACES OF AVOCADO SEEDLINGS

Abstract

Stomatal density, epidermal cell density and stomatal index, in the first eleven mature leaves of avocado seedlings were studied. Three avocado races (Guatemalan, Mexican and West Indian) were evaluated. It was found that up to the first seven leaves, West Indian seedlings had the lowest stomatal density. Mexican seedlings showed the highest stomatal density and the Guatemalans had intermediate values. In the eleventh leaf stomatal density was highest in the three races; in Mexican, West Indian and Guatemalan seedlings values were 419.3, 360.6 and 305.9 stomata/mm², respectively. In older leaves epidermal cell density was greatest in the Guatemalan race, followed by Mexican and West Indian races; and from the eighth leaf onwards the three races were similar, with a trend to increase. The stomatal index was similar in different leaf position on the stem, but with differences among the races as follows: Mexican>West Indian>Guatemalan.