携帯型マンセル色票計による野外でのトウツバキの花色測定  [in Japanese] Outdoor Measurements of Flower Colors of Camellia reticulata (Theaceae) Using a Portable Device that Indicates Values by the Munsell Color System  [in Japanese]

マンセル表色糸に従って検体の色を色相(hue),明度(value),彩度(chroma)の3属性の数値として表示するカラーリーダーCR-11(コニカミノルタセンシング(株)製)を用い,トウツバキの花色を調査した.楚雄市紫溪山に自生する1本の若いトウツバキについて,5花の全花弁の向軸面,背軸面の色を測定した結果,2花で最外側の花弁に,1花で内側の花弁1枚に違いが見られた他はすべて同じ数値(7.5RP4/12)であり,花色は個体内で安定していた.楚雄市紫溪山および黒牛山の樹齢500〜800年の自生トウツバキ古樹について測定した結果,個体内ではほとんど変異がなく,個体間では7.5RP4/12,10RP3/10,5RP4/12,10RP4/12などの花色の変異が見られた.園芸品種'大理茶'と'睡美人'について満開の花と老化した花とで測定を行ったところ,'大理茶'では7.5RP4/12,'睡美人'では2.5RP6/10が満開の花の最頻値であったが,老化した花では色相,明度,彩度に変化が生じていることが明らかになった.携帯型マンセル色票計による花色測定は,時間や調査環境など制約の多い野外調査で花色を記録する場合や,多量のデータを取って花色を比較分析する場合に優れた方法と考えられる.

The flower colors of Yunnan camellia (Camellia reticulata Lindl., Theaceae) were measured using a device that indicates values by the Munsell color system. The device (ColorReader CR-11, Konica Minolta Sensing, Co., Japan) indicates the numbers of three dimensions (H V/C) that specify the petal color. In a wild C. reticulata tree in Chuxiong City, Yunnan Province, China, five flowers (each having 5-8 petals) showed the same color (7.5RP 4/12) with few exceptions at the outermost petals. In five old trees (ages 200-600), the flower colors were indicated as 7.5RP 4/12, 10RP 3/10 and 5RP 4/12 and showed little variation within individuals. Two horticultural cultivars, 'Tali Camellia' and 'Sleeping Beauty', cultivated in the Kunming Botanical Garden, were measured. In 'Tali Camellia', the mode of petal colors in both fully bloomed and senescent flowers was 7.5RP 4/12, the same as in wild C. reticulata. In 'Sleeping Beauty', the petal color of freshly bloomed flowers was 2.5RP 6/10, while 2.5RP 6/8 in older flowers. Both freshly blooming and older flowers of 'Sleeping Beauty' showed the same "hue", however, the mean "value" of petal colors in older flowers was greater than that of freshly blooming flowers, and the mean "chroma" in older flowers was smaller than that of freshly blooming flowers. This device can be useful for outdoor measurement of flower colors for both wild and cultivated Yunnan camellia.