Abstract:
:This paper describes a new technique that can be used to study chloroplast volume regulation in vivo. Nuclear magnetic resonance spectroscopy was used to measure relative amounts of chloroplast water in Acer platanoides leaves as they dried in air, and also in leaf disks exposed to aqueous polyethylene glycol, sucrose, or glycerol. The chloroplasts retained a constant quantity of water as leaf water potentials varied between -0.05 and -1.90 MPa, indicating that volume regulation was effective throughout this range. The chloroplasts lost water when the water potential fell below -1.90 MPa, except when leaf disks were exposed to glycerol, suggesting that the lower limit of effective volume regulation is determined by physiological levels of osmotic solutes and that glycerol can be used for chloroplast osmoregulation.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
McCain DC,Markley JLdoi
10.1016/S0006-3495(92)81930-6subject
Has Abstractpub_date
1992-05-01 00:00:00pages
1207-12issue
5eissn
0006-3495issn
1542-0086pii
S0006-3495(92)81930-6journal_volume
61pub_type
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