Article contents
The influence of nitrogen, phosphate and potash on the secretion of nectar. part II
Published online by Cambridge University Press: 27 March 2009
Extract
1. The1951 clover experiment. No significant effects on the mean yield of nectar were obtained, but the higher dose of phosphate significantly increased the frequency of zero samples during August, the main flowering and sampling period; so also did the higher dose of potash in the presence of high nitrate. In general those treatments which depressed nectar secretion resulted in a larger proportion of flowers opening before mid-August. Accelerated flower production appeared to result from more rapid growth during August.
2. The 1952 clover experiment. The treatment effects on quantity of sugar per floret were compared with those on final stem weight. Treatment effects on sugar/floret on particular sampling occasions were compared with the effects on relative ‘growth rate’ during the preceding period. Additional phosphate always resulted in greater and more rapid growth, but it only reduced the nectar yield in the presence of the highest level of potash. In the presence of low doses of potash nectar secretion was consistently poor. Additional potash did not increase the nectar yield if it resulted in greater or more rapid growth; if it did not affect size or growth rate it increased the nectar yield. Clonal differences in nectar production were greater than treatment ones.
3. The responses of the four species used in this series of experiments are compared. The results of other workers on the effects of fertilizer treatments on nectar production are discussed in relation to those reported here. If the balance between different fertilizers and their effects on growth are considered, as well as nectar yields, contradictions between the results of various workers can be explained. It is suggested that when potash tends to limit growth nectar secretion is likely to be consistently poor, but that when growth tends to be limited by nitrogen or phosphate a relative surplus of potash will promote good secretion.
Reference is made to work on the relation of the sugar supply in plants to nectar secretion and on the relation of fertilizers to the sugar supply. Tentative recommendations are made which require confirmation in field tests.
- Type
- Research Article
- Information
- Copyright
- Copyright © Cambridge University Press 1954
References
REFERENCES
- 4
- Cited by