Sieve Elements in Isoetes coromandelina L.f. Collected from Rajasthan, India

摘要

Description is given of the structure of phloem cells studied in thin sections of wax embedded corm of Isoetes coromandelina, collected from Dausa, Rajasthan, India. Both primary and secondary phloem cells are present on inner side of the cambium, which cut off parenchymatous secondary cortex on outside. Sieve cells have sieve plates/sieve areas of different shape and sizes, uni to biseriate or multiseriate on lateral walls. Sieve pores visible on some sieve plates. Various views expressed in literature on morphology of primary and secondary phloem cells are discussed in this paper.