Morphological, stomatal, pigmentation, and biomolecular characteristics of a few epiphytic orchid species of India

In order to identify suitable species that can be used for cross-breeding and propagation for horticulture purposes four endemic and epiphytic orchid species, Aerides crispa Lindl., A. maculosa Lindl., A. ringens Fischer. and A. odorata Lour. were studied by comparing their leaf morphology, stomata, pigmentation, and biomolecules. Standard methods were used for the evaluation. A. odoratum, native to the lowest altitude, was characterized by thin, long leaves with the lowest specific leaf area and higher water content. Among the four species studied, stomata were bigger in size and less in number in A. odoratum. Maximum total soluble sugars, soluble proteins, amino acids, and starch contents, an indicator of a better photosynthesis rate were noted in A. odoratum. Total chlorophyll and carotenoid contents per unit leaf area were higher in A. odoratum and A. ringens. Our results concluded that variation in environmental temperature, humidity, sunlight intensity, and exposure of orchids at different altitudes may cause alteration in traits that can be inherited over a period.