³²P mobility in detached leaf of several crop plants

Abstract

Detached leaves of several crop plants were cultured in a nutrient solution containing ³²P, and the ³²P mobility between and within organs was investigated. The results obtained were as follows: 1) In soybean and adzuki bean, ³²P was well distributed all over the leaf blade and petiole within 24 h after ³²P absorption, though the transfer of ³²P from the leaf vein to the mesophyll varied among the varieties. 2) In rice, ³²P reached the middle or proximal part of the leaf blade within 48 h after ³²P absorption. The gradient of ³²P density decreased distally. 3) In maize and pumpkin, a small amount of ³²P reached the leaf blade; in maize, the gradient of ³²P density was similar to that in rice, though ³²P was retained in the whole petiole in pumpkin. Besides transpiration, ³²P transfer from xylem to mesophyll and structures of leaf tissues could be considered to regulate the ³²P mobility.

Key Words:

• detached leaf
• ³²p distribution
• ³²P mobility
• transpiration
• xylem flow