Study on starch in the leaves of Alocasia odora Spach (Araceae) I. Seasonal and daylong variation of starch in the leaves.(Department of Agricultural Chemistry)

クワズイモ葉の澱粉含量およびアミロペクチン/アミロース比の経時および季節的変化を調べた。クワズイモ葉500gから澱粉1.7gを得た。収率は0.34%(対新鮮葉)であった。また調製した澱粉1.00gからアミロースおよびアミロペクチンそれぞれ0.22gおよび0.74g得た。クワズイモ葉から澱粉の単離を行い, さらにアミロースとアミロペクチンに分離, それぞれをヨウ素呈色後, 可視光線吸収スペクトルを測定した結果, 極大吸収波長はそれぞれ550nm, 555nmおよび515nmであった。クワズイモ葉澱粉含量およびアミロペクチン/アミロース比の経時変化を調べたところ, 澱粉含量は日中多く, 夜間減少することが解った。一方, アミロペクチン/アミロース比は日中低く, 夜間高い値を示すことが解った。澱粉含量の季節的変化を月別に調べたところ, 10月に最も多く(平均2.75%), 次いで11月(2.14%), 2月(2.14%), 12月(1.86%)および1月(1.53%)の順に高い値を示した。アミロペクチン/アミロース比の季節的変化を月別に調べたところ, 1月に最も高く(4.60), 次いで11月(4.38), 10月(4.17), 12月(4.15)および2月(3.96)の順に高い値を示した。Seasonal and daylong variation of starch and amylopectin/amylose ratio in the leaves of Kuwazu-imo (Alocasia odora Spach) were investigated. The results obtained were as follows; 1 Starch was prepared from the leaves of Kuwazu-imo by the yeild of 0.34% of the fresh tissues. Amylose and amylopectin were prepared from 1.00g of the starch by the yield of 22% and 74%, respectively. 2 The iodine coloration spectrum of starch, amylose and amylopectin showed the characteristics of their own. The content of starch in the leaves of Kuwazu-imo was constant in the day time and kept high value, however it showed low value in the night time. The amylopectin/amylose ratio of Kuwazu-imo showed high value in the night time but showed low value in the day time. Quantitative determinations of starch in the leaves of Kuwazu-imo were carried out throughout five months. The content of starch reached the maximum value in October, and the value gradually decreased from November till January