Book contents
- Frontmatter
- Contents
- INTRODUCTION
- CHAPTER I THE CIRCUMNUTATING MOVEMENTS OF SEEDLING PLANTS
- CHAPTER II GENERAL CONSIDERATIONS ON THE MOVEMENTS AND GROWTH OF SEEDLING PLANTS
- CHAPTER III SENSITIVENESS OF THE APEX OF THE RADICLE TO CONTACT AND TO OTHER IRRITANTS
- CHAPTER IV THE CIRCUMNUTATING MOVEMENTS OF THE SEVERAL PARTS OF MATURE PLANTS
- CHAPTER V MODIFIED CIRCUMNUTATION: CLIMBING PLANTS; EPINASTIC AND HYPONASTIC MOVEMENTS
- CHAPTER VI MODIFIED CIRCUMNUTATION: SLEEP OR NYCTITROPIC MOVEMENTS, THEIR USE: SLEEP OF COTYLEDONS
- CHAPTER VII MODIFIED CIRCUMNUTATION: NYCTITROPIC OR SLEEP MOVEMENTS OF LEAVES
- CHAPTER VIII MODIFIED CIRCUMNUTATION: MOVEMENTS EXCITED BY LIGHT
- CHAPTER IX SENSITIVENESS OF PLANTS TO LIGHT: ITS TRANSMITTED EFFECTS
- CHAPTER X MODIFIED CIRCUMNUTATION: MOVEMENTS EXCITED BY GRAVITATION
- CHAPTER XI LOCALISED SENSITIVENESS TO GRAVITATION, AND ITS TRANSMITTED EFFECTS
- CHAPTER XII SUMMARY AND CONCLUDING REMARKS
- INDEX
CHAPTER IX - SENSITIVENESS OF PLANTS TO LIGHT: ITS TRANSMITTED EFFECTS
Published online by Cambridge University Press: 29 August 2010
- Frontmatter
- Contents
- INTRODUCTION
- CHAPTER I THE CIRCUMNUTATING MOVEMENTS OF SEEDLING PLANTS
- CHAPTER II GENERAL CONSIDERATIONS ON THE MOVEMENTS AND GROWTH OF SEEDLING PLANTS
- CHAPTER III SENSITIVENESS OF THE APEX OF THE RADICLE TO CONTACT AND TO OTHER IRRITANTS
- CHAPTER IV THE CIRCUMNUTATING MOVEMENTS OF THE SEVERAL PARTS OF MATURE PLANTS
- CHAPTER V MODIFIED CIRCUMNUTATION: CLIMBING PLANTS; EPINASTIC AND HYPONASTIC MOVEMENTS
- CHAPTER VI MODIFIED CIRCUMNUTATION: SLEEP OR NYCTITROPIC MOVEMENTS, THEIR USE: SLEEP OF COTYLEDONS
- CHAPTER VII MODIFIED CIRCUMNUTATION: NYCTITROPIC OR SLEEP MOVEMENTS OF LEAVES
- CHAPTER VIII MODIFIED CIRCUMNUTATION: MOVEMENTS EXCITED BY LIGHT
- CHAPTER IX SENSITIVENESS OF PLANTS TO LIGHT: ITS TRANSMITTED EFFECTS
- CHAPTER X MODIFIED CIRCUMNUTATION: MOVEMENTS EXCITED BY GRAVITATION
- CHAPTER XI LOCALISED SENSITIVENESS TO GRAVITATION, AND ITS TRANSMITTED EFFECTS
- CHAPTER XII SUMMARY AND CONCLUDING REMARKS
- INDEX
Summary
No one can look at the plants growing on a bank or on the borders of a thick wood, and doubt that the young stems and leaves place themselves so that the leaves may be well illuminated. They are thus enabled to decompose carbonic acid. But the sheath-like cotyledons of some Gramineæ, for instance, those of Phalaris, are not green and contain very little starch; from which fact we may infer that they decompose little or no carbonic acid. Nevertheless, they are extremely heliotropic; and this probably serves them in another way, namely, as a guide from the buried seeds through fissures in the ground or through overlying masses of vegetation, into the light and air. This view is strengthened by the fact that with Phalaris and Avena the first true leaf, which is bright green and no doubt decomposes carbonic acid, exhibits hardly a trace of heliotropism. The heliotropic movements of many other seedlings probably aid them in like manner in emerging from the ground; for apogeotropism by itself would blindly guide them upwards, against any overlying obstacle.
Heliotropism prevails so extensively among the higher plants, that there are extremely few, of which some part, either the stem, flower-peduncle, petiole, or leaf, does not bend towards a lateral light. Drosera rotundifolia is one of the few plants the leaves of which exhibit no trace of heliotropism. Nor could we see any in Dionæa, though the plants were not so carefully observed.
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- Information
- The Power of Movement in Plants , pp. 449 - 492Publisher: Cambridge University PressPrint publication year: 2009First published in: 1880