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Diurnal osmotic cycling in cotton leaves as an indicator of source–sink balance
Author(s) -
RADIN J. W.,
MAUNEY J. R.,
GUINN G.
Publication year - 1986
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11611796
Subject(s) - turgor pressure , osmotic pressure , cycling , sink (geography) , gossypium hirsutum , osmoregulation , horticulture , chemistry , botany , agronomy , biology , salinity , ecology , geography , cartography , archaeology , history
Diurnal cycling of osmotic potential was studied in leaves of cotton plants ( Gossypium hirsutum L.) grown in the field. Osmotic potential was determined by a pressure‐volume procedure as the value coinciding with zero turgor. In plants grown under favourable conditions (no water stress or N stress), osmotic potential at zero‐turgor measured at midday was initially about 0.3 MPa lower than before dawn, but this cycling disappeared during the season as the number of fruits per plant increased. In water‐stressed or N‐deficient plants, osmotic cycling was decreased or even eliminated. Across treatments, cycling of osmotic potential occurred only when plants carried at least 560 cm 2 of leaf area per fruit. The results are interpreted to mean that diurnal cycling of osmotic potential reveals a ‘sink‐limited’ condition within the plant.