Shoichi Nakagawa

Biologically active gibberellins in immature seeds of Pyrus serotin

Abstract Biologically active gibberellins were isolated from immature seeds of Japanese pear ( Pyrus serotina ). The major one was tentatively identified as GA 4 by selected ion monitoring. Evidence for the possible presence of GA 7 in the seeds was inconclusive but GA 3 was not detected by either the rice seedling or barley half-seed bioassay.

Effect of controlled release fertilizer on the growth of young satsuma mandarin trees

Two types of controlled release fertilizer (Nutricote 100 and 180) were applied to 2‐year‐old potted satsuma mandarin (Citrus reticulata Blanco), ‘Okitsu wase’. For comparison a common slow‐acting fertilizer, CDU, ammonium sulfate(NH4‐N) and sodium nitrate (NO3‐N) were also used. In case of slow acting fertilizers 6g(x1) and 12g(x2)N per pot were mixed into the upper surface soil in April, while in NH4‐N and NO3‐N,2g(x1) and 4g(x2)N per pot were applied in the same manner in April, June and August, 1985. Shoot growth, shoot pruning weight and trunk diameter increase of the trees receiving Nutricote 100 and 180 were greater than any of those receiving other fertilizers. When N application rate was doubled in NH4‐N(x2), shoot growth became comparable to that of trees receiving Nutricote. Return bloom in Nutricote 100(x1) and 180(x1) was 192.3 and 167.6, while that in CDU(x1,x2) and NO3‐N(x2) was 12.0, 9.8 and 16.4, respectively.