REGULARITY IN VARIATION OF LEAF COLOR AND NITROGEN DISTRIBUTION IN HALF-LEAF BLADES BY LEAF POSITION ON THE STEMS OF RICE PLANTS .1. VARIATION OF CHLOROPHYLL METER VALUES AND MECHANISM OF LEAF FORMATION

We clarified that the degrees of the difference in color between outsi de and inside half-leaves were unexpectedly large, which ranged from 1 .3 to 5.4 values by the Minolta chlorophyll meter SPAD-502 (correspond ing to 0.1 to 0.5% N content) in three Japanese and three American cul tivars. The color intensity of a half-leaf with an outside margin in t he Leaf sheath wrapping (outside half-lean was deeper and its width wa s narrower than that of an inside half-leaf. There was a regularity in the growth pattern of leaves, namely, a deep-colored half-leaf (outsi de half-leaf) and a light-colored half-leaf (inside half-lean were dis posed on the stem with a regular alternation in order of the well-know n right- and left-handed emergence of leaves. This meant that the posi tion of an outside (or inside) half-leaf in the (n)th leaf was governe d concordantly by the previous (n-I)th leaf. This concordance tended t o appear from the third leaf position, and the concordance ratio was l ow at lower early-emerging leaves, and high at upper late-emerging lea ves as already described. A 100% ratio of concordance was obtained at the higher Leaf positions than at the sixth or seventh leaf in this ex periment. The chance of a left (or right) half-leaf becoming an outsid e (or inside) half-leaf was approximately 50%. When seeds were centrif ugalized to determine the effects of centrifugal force on leaf emergen ce at germination, the chance of the centrifugalized side becoming an outside half-leaf was increased.