 BackResearch Article ScienceAsia 4 (1978): 127-138 |doi: 10.2306/scienceasia1513-1874.1978.04.127
SOME ASPECTS OF PHLOEM STRUCTURE AND DEVELOPMENT IN MARSILEA QUADRIFOLIA L.
MALEEYA KRUATRACHUESummary: Sieve elements in the phloem from rhizomes of Marsilea quadrifolia L. were examined with the electron microscope. Very young sieve elements are characterized by the presence of the refractive spherules, which arise in the cisternae of the endoplasmic reticulum. As sieve element differentiation proceeds, the delimiting membranes of many of the refractive spherules begin to fuse with the plasmalemma and the material comprising the spherules is liberared into the region of the wall. At maturity the enucleate, plasmalemma-lined sieve element contains a sparse, parietal network of tubular endoplasmic reticulum, plastids and mitochondria. The sieve area pores are quite small in size and are lined by the plasmalemma. Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand Received 1 June 1978
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