The effects of an osmoticum (mannitol) on growth, water content, respiration, and proline content in epicotyls of etiolated two-day-old (S2) and three-day-old (S3) pea (Pisum sativum L., cv. Flora-2) seedlings were studied. Water deficit was produced by placing plant roots in 0.6 M mannitol for 2–4 days. Control S3 epicotyls contained more water than S2 epicotyls; they were also characterized by more intense mitochondrial activity (in state 3, V 3) and by the higher value of the respiratory control (RC) due to a fourfold decrease of proportion of weakly phosphorylating cyanide-resistant respiration (CRR). After 2-day-long treatment with the osmoticum, S2 epicotyls lost more water than S3; water deficit in them attained 40% (28% in S3). In S3 treatment, epicotyls continued to grow at the almost unchanged rate, and the content of proline in them changed insignificantly, whereas in S2 seedlings epicotyl growth stopped, and proline accumulated in them. In the presence of the osmoticum, V 3 and RC reduced, but in S3 treatment they retained higher than in treatment S2. In mitochondria of S3 subjected to dehydration, the proportion of the cytochromic pathway of oxidation (V cyt) remained high, but the absolute values of the respiration rate reduced, whereas in S2 both these indices reduced and the proportion of CRR increased. After rewatering, indices of mitochondrial activity (the rate of substrate oxidation, RC value) were restored, but in S3 they were higher. The ratio of V cyt to CRR in S3 shifted toward CRR, whereas in S2, in contrast, it was shifted toward V cyt. When temperature during seedling growth and experiment performing was declined from 22°C (in control) to 18°C, growth of S3 epicotyls was retarded to the rate characteristic of S2 at 22°C. Under the effect of osmoticum, they, like S2, acquired a capacity to accumulate proline. Nevertheless, mitochondrial activity in such S3 turned out to be higher than in S2 grown at 22°C. The results obtained than, as distinct from traditional notes, 3-day-old pea seedlings manifested the higher tolerance to water deficit than 2-day-old seedlings.
Russian Journal of Plant Physiology – Springer Journals
Published: Feb 26, 2012
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
All the latest content is available, no embargo periods.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud