Foliar Micromorphology of In Vitro-cultured Shoots and Field-grown Plants of Passiflora foetida

The present report describes the development of quantitative and qualitative foliar micromorphological and architectural features in the field environment which elucidated the adaptation of micropropagated plants of Passiflora foetida L. in the natural soil conditions. The field environment (high light intensity in comparison to in vitro culture conditions) promotes the autotrophy through decrease in stomatal index (from 23.2 ± 0.15 to 21.0 ± 0.19), increased vein-islets (from 10.0 ± 0.14 to 15.6 ± 0.24 per square millimeters) and veinlet terminations (from 1.6 ± 0.14 to 5.0 ± 0.20 per square millimeters), and trichome density in P. foetida plantlets. The in vitro and field grown leaves mostly possessed anomocytic and anisocytic types of stomata. Two types of trichomes were observed on the surface of leaves of in vitro as well as field transferred plants of P. foetida: the unicellular hairy trichomes (non-glandular), and the multicellular (glandular) trichomes. The trichomes density was less under in vitro conditions as compared to the in vivo environments. The new leaves formed during the ex vitro rooting stage (in greenhouse) and after transplantation of plantlets to the field exhibited the development of adaptive micromorphological features in micropropagated plants, which enabled them to survive under field conditions.