Seed Microstructures of The Andaman Padauk ( Pterocarpus dalbergoides )

Andaman padauk (Pterocarpus dalbergioides Roxb.) is an important endemic tree species of the Andaman Islands, India, belonging to the family Fabaceae. We studied the seed microstructures which provide information on the physiological features of germination (i.e. factors responsible for the resumption of growth of embryo). Seed anatomy/morphostructures revealed information on its germination physiology (for ex situ conservation), dormancy barriers and further taxonomical classification. The seed samples were examined under a scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) was used to study the chemical composition of the seeds. In the SEM images, seed thickness of the parenchyma layer was about 53.16 °m, while that of the osteosclereids (OH) and macrosclereids (MH) layers was 23.95 and 84.68 °m respectively. The size of OS cells had a length of 25.81–34.56 °m; diameter 12.14– 16.5 °m and width 7.97–12.60 °m. FTIR spectra of padauk seed assignments were used to determine the probable chromophoric groups that are likely to be present in the seeds. Various functional groups such as N–H, O–H, C–H, C=O, C–O were identified in the seeds. The results indicate the presence of carbohydrates, amino acids, amides, esters, ethers, phenols, proteins and fats in the padauk seeds. These observations would be helpful in correlating several aspects of seed germination/dormancy physiology of this endemic species, which has applications in ex situ conservation.