ESJ56 一般講演（口頭発表） B1-09
*Gomes, PIA （Saitama Uni.）, Asaeda, T.（Saitama Uni.）
Characean algae, Nitella pseudoflabellata was investigated for the growth dynamics, morphology and calcification against variable levels and combinations of Ca (4-120 mg/L) and Mg (2-120 mg/L). Both these metals are freely available in ecosystems that Chara colonize. Their concentrations are habitat specific and subject to temporal variations. Shoot elongations were significantly correlated ( r = 0.96, P < 0.05) with Ca in water (CaW) and in case of Mg in water (MgW) it was rather marginal. However units exposed to MgW achieved relatively high elongation at the end of 10th week. Higher the CaW; branchlets (especially secondary) seemed to be trimmed, whereas MgW showed otherwise with noticeable vertical elongation. Results based on redundancy analysis (RDA) suggest plant Ca levels showing less positive correlation with CaW, and strong positive correlation between plant Mg levels and MgW. This conclusion is further obvious in the long run. Though MgW resulted in less Ca in plants, analyses suggest impact is rather on the external Ca accumulation (i.e. calcification). Although MgW resulted in satisfactory growth of Nitella , less calcification might result in decalcification of lakes water and subsequent less reduction in phosphorous.