Effects of pH on sex organ differentiation and sexual reproduction in the endangered aquatic fern Ceratopteris p teridoides

Abstract

Abstract Ceratopteris pteridoides is an endangered aquatic floating fern in China. The effects of different pH values on spore germination, sex organ differentiation in C. pteridoides are studied by a control experiment of setting pH gradients of 4, 5, 5.5, 6, 6.3, 6.5, 7, 7.5, 8, 9 in this paper. The results show that spore germination rates (26.1% and 19.30%, respectively) in pH = 4 and pH = 9 are significantly lower (P<0.05) than in reference group (45.63%, pH = 6.3), indicating that spore germination in C. pteridoides is adaptable over a wide range of pH. The optimum pH for spore germination, sex organ differentiation, and gametophyte development in C. pteridoides is between 6 and 7. An ANOVA of the different pH values after cultivation showed that hermaphrodite gametophyte emergence rates in 4, 5, 7.5, 8, 9 pH values were significantly lower (P<0.05) than those of the reference group. This may pose a threat to the sexual reproduction of the wild population of Ceratopteris pteridoides .