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THE HETEROCYSTS OF THE BLUE‐GREEN ALGA NOSTOCHOPSIS LOBATUS: EFFECTS OF CULTURAL CONDITIONS
Author(s) -
TIWARI D. N.
Publication year - 1978
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1978.tb01639.x
Subject(s) - heterocyst , biology , ammonium , botany , cyanobacteria , trichome , chemistry , anabaena , genetics , bacteria , organic chemistry
SUMMARY The branched filaments of Nostochopsis lobatus form infrequent intercalary heterocysts in the main trichome while the short lateral branches (1–4 celled) characteristically produce only a terminal heterocyst when the alga is grown in a medium devoid of combined nitrogen. In the presence of ammonium nitrogen, intercalary heterocysts are not formed but the lateral heterocysts enlarge to assume a balloon‐like appearance; they undergo division in situ and liberate 3–5‐called germlings. These germlings grow and produce similar heterocysts and the cycle is repeated until growth ceases. Heterocysts are produced at the terminal ends of the long lateral branches during the later stages of growth in ammonium medium; they are not formed, in this position, in cultures grown in nitrogen‐free medium. The possible role of lateral heterocysts in controlling growth and development of long laterals is discussed.