Anatomical aspects of juice sac and mechanism of solute translocation and accumulation in citrus fruits.

Research Project

Project/Area Number	61560042
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	園芸・造園学
Research Institution	Meijo University
Principal Investigator	NAOSUKE Nii College of Agriculture. Meijo Univerisity, 農学部, 助教授 (30103261)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥1,300,000 (Direct Cost: ¥1,300,000) Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Keywords	Juice sac enlargenent / Juice sac ultrastructure / Nonvasuclar translocation / Sugar accumulation / 砂じょうの組織培養
Research Abstract	1. Anatomical aspects of juice sac in satsuma mandrin fruits. Anatomical features of developing juice sac were studied by light and transmission electron microscopy. The development of juice sace commenced on the inner wall of the locules just before anthesis. Differentiation into stalk and sac bofy began when the juice sace were about 0.7 mm in lenght. Accmulation of sugras into the juice sace occutted after they had attained full size. There was no evidence of vascular or tracheid tissue in the stalk of the juice sac. Plasmodesmata were abundant in the thin walls of the parenchyma cells of the juice sac stalk. Plasmodesmatal frquencies increased during juice sac enlargenment. In the mature juice sac stalk, cell wall profubverance and high frequencies of plasmodesmata, mitrochondria, and samall vaculoes were observed. In conclusion, it is suggested that the parenchyma cells of the juice sac stalk are a major translocatory pathway. Solutes may ve accumulated in the juice sac via a symplastic route via plasmodesmata. 2. Growth and development of citrus juice sac explants in vitro. Growing juice sac explants from 30 citrus species were cultured on June 26 and August 5 in vitro on MS media (1962). There was no difference in the enlargement of juice sac in comparison between PH 4.5and 5.6 and between 25゜C and 30゜C in both seasons. Culture of juice sac explants resulted in a marked growth of juice sac, from 'Tengu', 'Kobayashi Mikan','Sugiyama unshiu', 'Miyagawawase', on June 26 and from 'Naruto', 'Kobayashi Mikan', 'Sugiyama unshiu', 'Miyagawa-wase', 'Hirado buntan', 'Lisbon', Hyuganatsu', 'Yama Mikan' on August 5. The results suggest that the study of this juice sac system in vitro may contribute to a better understanding of physiological and anatomical development in citrus furits.