COMPARATIVE STUDY OF POLLEN AND PISTIL IN CROCUS SATIVUS L. (IRIDACEAE) AND ALLIED SPECIES

Abstract

Crocus sativus L. is mainly known for the production of the drug saffron. Because of its sterility, it is propagated vegetatively by means of corms. To gain information on the reproductive biology of saffron and allied species, a comparative study on pollen and pistil of Crocus sativus L., C. cartwrightianus Herb., C. thomasii Ten. and C. hadriaticus Herb. was carried out. Pollen and pistils gathered at anthesis were examined by light (LM) and scanning electron microscopy (SEM). Pollen shape and size, anomalous pollen grain percentage, pollen viability, pollen germination in vitro and on self-, and cross-pollinated stigmas were examined. Pistils at different developmental stages were examined by light microscopy. C. hadriaticus had the smallest pollen; C. sativus showed a higher percentage of anomalous and aborted grains and a lower percentage of viable grains. Pollen germination in vitro as well as on differently pollinated stigmas was lowest in C. sativus. Pistil organization was similar in all the species, but ovule number and integuments varied. Embryo sacs mature early, and female gametophyte development is regular for some days after flower anthesis. Capsules with seeds were obtained from all diploid species as well as in saffron after free- and cross-pollination. Results confirm that sterility in C. sativus is mainly confined to pollen.