Influence of pH on Sporulation, Spore Germination and Germling Survival in Blue‐green Algae

Abstract

AbstractAn investigation is made on the influence of the pH‐value in the range of pH = 4.5 to 11.0 on sporulation, germination and germling development of Anabaena fertilissima and Anabaenopsis arnoldii, isolated from the Sambhar Salt Lake, Rajasthan. Maximum rates of germination were obtained with Anabaena at pH = 7.0… 10.5, with Anabaenopsis at pH = 7.0 to 8.5. With both species, sporulation occurs in the same pH‐ranges, Anabaena dying without sporulation in the range of pH = 5.5… 6.5 and above pH = 10.5 and Anabaenopsis surviving without sporulation above pH = 9.5. With Anabaena the germling growth steadily increases from pH = 7 to 10.5, whereas Anabaenopsis shows a maximum at pH = 7 and at any other pH‐value growth is considerably lower. Moreover, spore germination is bound to an exchange of the medium. In agreement with these experimental findings concerning the cultures, from July to February Anabaenopsis occurs in the Sambhar Lake as a vegetative form with a partial mass development, and from March to June it survives as a spore. Anabaena, however, has only a short vegetative phase in June, and it survives the remaining part of the year as a spore. Thus, the fast germination and sporulation in the range of higher alkalinity is the ecological strategy for Anabaena to resist the competition offered by Anabaenopsis.