Phenology of sexual reproduction of Chara fibrosa and Chara zeylanica
1996
Guha, P. (Indian Institute of Technology, Kharagpur (India). Horticulture Section)
Pot experiments and rice-field surveys were carried out (simultaneously during 1992 and 1993) at Kharagpur and Contai subdivisions of Midnapore district of West Bengal, India, respectively, to study the different aspects of the phenology of the sexual reproduction of Chara. In pot experiments, Chara zeylanica and Chara fibrosa were grown from the soil-borne oospores in earthen pots filled with water while in rice fields, 50 sites in 5 different villages were selected for recording the observations on the algae. The results showed that the globules became round and pink at maturity, and disintegrated soon thereafter. The nucleus however, turned oval at maturity with two different colors, i.e. saffron in Chara zeylanica and black in Chara fibrosa indicating completion of the life cycle of the weed. The total time required for this was not fixed and varied widely from 36-59 days after germination, including 22-36 days for initiation and 14-23 days for maturation thereafter. The reproductive capacity of the weed was high. The highest number of oospores produced per plant, per mg dry thalli and also per hectare was estimated to be 397, 23 and 48*10*[9) respectively at about three months' stage of growth. The oospore drop-out from these living plants was very low, being at the most 3.5 percent only. The implication of this study for controlling this algal weed in water-logged rice fields is discussed.
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