Abstract
The capacity of tobacco (Nicotiana rustica) leaf discs to incorporate l-leucine 14C into proteins was measured. Leaf discs were obtained from plants which experienced soil water depletion, or which were exposed to a saline or osmotic stress in the root medium. The stresses were brief of relatively short duration and water potential did not decrease below 4 bars in the root media. Leaf discs were sampled 2 hours after stress removal, achieved by reirrigation, or replacement of saline and osmotic solutions with normal nutrient solution. Plants were always turgid when leaves were sampled.
All stressed tissues showed reduced capacity to incorporate l-leucine 14C into protein. The reduction was about 50% and could not be attributed either to reduced uptake into the discs, or to possible isotopic dilution. Incorporation decreased progressively with leaf age in control discs as well as in stressed leaf discs. At all ages tested, incorporation in stressed discs was lower than that of the control. Full recovery of incorporation capacity in stressed discs was obtained when discs were sampled 72 hours after stress removal but not earlier.
Kinetin pretreatment prior to incubation with labelled leucine partially restored incorporation in stressed discs. The differences in response to kinetin of stressed and control discs suggest a lower endogenous level of cytokinins in the stressed discs. The results were qualitatively similar regardless of the kind of stress given to the plants during pretreatment. This supports the hypothesis that the normal supply of root cytokinins is important in shoot metabolism.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Barnett N. M., Naylor A. W. Amino Acid and protein metabolism in bermuda grass during water stress. Plant Physiol. 1966 Sep;41(7):1222–1230. doi: 10.1104/pp.41.7.1222. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CRELIN E. S. Mitosis in adult cartilage. Science. 1957 Apr 5;125(3249):650–650. doi: 10.1126/science.125.3249.650. [DOI] [PubMed] [Google Scholar]
- Kende H. KINETINLIKE FACTORS IN THE ROOT EXUDATE OF SUNFLOWERS. Proc Natl Acad Sci U S A. 1965 Jun;53(6):1302–1307. doi: 10.1073/pnas.53.6.1302. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Weiss C., Vaadia Y. Kinetin-like activity in root apices of sunflower plants. Life Sci. 1965 Jul;4(13):1323–1326. doi: 10.1016/0024-3205(65)90084-6. [DOI] [PubMed] [Google Scholar]
- Went F. W. SPECIFIC FACTORS OTHER THAN AUXIN AFFECTING GROWTH AND ROOT FORMATION. Plant Physiol. 1938 Jan;13(1):55–80. doi: 10.1104/pp.13.1.55. [DOI] [PMC free article] [PubMed] [Google Scholar]