Nutriophysiology of stock (Matthiola incana R. Br.) I. Morphological characteristics of the individual leaves developing and their ontogenic changes with respect to nitrogen and phosphorus.

摘要

Changes in leaf area, leaf weight, total N, NO3-N and P were investigated in individual leaves of M. incana cv. Asanami. The final leaf number was 51, and the maximum leaf area at leaf positions 15-20 differed from that at positions 33-36. The dry weights (DW) of the lower leaves decreased little with aging, although N and P were translocated from the lower leaves to the upper leaves up to leaf position 30. The total N remained almost constant at 4.5-5.0% in actively developing leaves, but it decreased with age. P was higher in young leaves than in older leaves until the day before anthesis, when it decreased above position 25 to <0.35%. The translocated quotients (%) of N and P decreased with increasing leaf position from 8 to 30. NO3-N in leavesabove position 5 decreased with increasing node length. The peak translocated quotient occurred at position 18. These changes in DW, N and P in individual leaves were used to classify the leaves into 3 groups. These were: lower leaves (positions 1-7); middle leaves (positions 8-30); and upper leaves (above position 31). Lower leaves which developed slowly had higher translocated quotients of N or P. When middle leaves were completing their development, N and P were retranslocated without any decrease in leaf dry matter contents, and flower buds became visible. When upper leaves continued to develop, no export of N or P was detected.