Biological Effects of Radiation: Mechanism and Measurement of Radiation, Applications in Biology, Photochemical Reactions, Effects of Radiant Energy on Organisms and Organic Products - Vol. 2

By Benjamin M. Duggar | Go to book overview

arbitrary "lithopone units" (L. U.), and they demonstrated for Pulmonaria officinalis the relation which exists between the number of L. U. and the time which must elapse (latent period) before the death of the epidermal cells. Younger leaves were found to be more sensitive than the older ones. They present a curve showing the relationship between the intensity of the treatment and the latent period and point out that there is also a relationship between the thickness of the cutin and the sensitiveness of the leaf. Among the histological details given of the effect of ultra-violet light on leaves, they show not only that there are the changes within the epidermal cells, but also that the vacuolization and destruction of the chloroplasts and the collapse of the palisade cells take place with increased dosages.

Martin and Westbrook also tested the effects of temperature during the period of treatment, and for the latent period they found that differences of temperature between 5° and 25°C. have little effect upon the rate of browning of the epidermis. These authors also discuss the relationship between the erythema dose of the human skin and the dose causing browning of the leaves, and point out that whereas many have attempted to draw a parallel between these superficial effects, the skin recovers and the pigmentation is produced within the cytoplasm without killing cells, while the plant epidermis is killed and does not recover.

There is a structural basis for the claim that the cutin of plants is relatively opaque to ultra-violet rays. Köhler (17, 18), who used the cadmium line (2750 Å) in the photomicrography of plant tissues, shows figures in which woody cell walls and cork cells are nearly impenetrable, whereas the cuticle of leaves and stems, even in very thin places, is impenetrable to these very short rays. Metzner (22) shows that there is a similar opaqueness of cuticular and other plant-cell walls to the longer ultra-violet rays (3500 to 4000 Å) which may play a role in the influence of the sun's radiation, especially at high altitudes; thus the ultra- violet rays usually do not enter the plant and probably do not play an important formative role in nature except in the structure of alpine plants.


REFERENCES

1. BAILEY L. H. "Electricity and plant growing". Mass. Hort. Soc. Trans. 1894: 54-79. 1894.

2. BEAUVERIE J., and P. CORNET. "Action des rayons ultra-violets sur la structure cellulaire dans la feuille et le bourgeon d'Elodea canadensis". Compt. Rend. Soc. Biol. [Paris] 102: 775-777. 1929.

3. BURGERSTEIN ALFRED. Die Transpiration der Pflanzen. Jena, 1904.

4. BURGERSTEIN ALFRED. Transpiration der Pflanze. Zweiter Teil (Ergänzungsband). Jena, 1920.

5. DANE H. REBECCA. "The effect of ultra-violet radiations upon soybeans". Science 66: 80. 1927.

6. DAVENPORT C. B. Experimental morphology. New York, 1908.

7. DEHÉRAIN P. P. "Expériences sur l'influence qu'exerce la lumière électrique sur le développement des végétaux". Annales Agron. 7: 551-575. 1881.

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Biological Effects of Radiation: Mechanism and Measurement of Radiation, Applications in Biology, Photochemical Reactions, Effects of Radiant Energy on Organisms and Organic Products - Vol. 2
Table of contents

Table of contents

  • Title Page iii
  • Contents v
  • Xix Photoperiodism 677
  • Introduction 677
  • References 709
  • Xx Plant Growth in Continuous Illumination 715
  • References 725
  • Xxi the Effects of Light Intensity Upon Seed Plants 727
  • Introduction 727
  • References 757
  • Xxii Effects of Different Regions of the Visible Spectrum Upon Seed Plants 763
  • Introduction 763
  • Concluding Remarks 787
  • References 788
  • Xxiii Effect of the Visible Spectrum Upon the Germination of Seeds and Fruits 791
  • References 823
  • Xxiv the Effects of Visible and Ultra-Violet Radiation on the Histology of Plant Tissues 829
  • References 838
  • Xxv Some Infra-Red Effects on Green Plants 841
  • References 851
  • Xxvi the Effect of Ultra-Violet Radiation Upon Seed Plants 853
  • Introduction 853
  • Concluding Remarks 881
  • References 882
  • Xxvii the Effects of Radiation on Fungi 889
  • Introduction 889
  • References 910
  • Xxviii the Problem of Mitogenetic Rays 919
  • Introduction 919
  • Conclusions 944
  • References 946
  • Xxix Effects of X-Rays Upon Green Plants 961
  • Introduction 961
  • General Summary 980
  • References 983
  • Xxx the Effects of Radium Rays on Plants 987
  • References 1009
  • Xxxi the Light Factor in Photosynthesis 1015
  • References 1051
  • Xxxii the Influence of Radiation on Plant Respiration and Fermentation Charles J. Lyon 1059
  • Introduction 1059
  • Summary 1071
  • References 1072
  • Xxxiii Growth Movements in Relation to Radiation 1073
  • Xxxiv Chlorophyll and Chlorophyll Development in Relation to Radiation 1093
  • References 1104
  • Xxxv Radiation and Anthocyanin Pigments 1109
  • Introduction 1109
  • Conclusion 1116
  • References 1118
  • XXXVI - Effects of Radiation on Bacteria 1119
  • References 1141
  • Xxxvii the Effects of Radiation on Enzymes 1151
  • References 1160
  • Xxxviii Induced Chromosomal Aberrations in Animals 1167
  • Introduction 1167
  • References 1202
  • Xxxix Radiation and the Study of Mutation in Animals 1209
  • Introduction 1209
  • References 1252
  • Xl Induced Mutations in Plants 1263
  • Introduction 1263
  • References 1278
  • Xli Induced Chromosomal Alterations 1281
  • References 1293
  • Xlii Induced Chromosomal Alterations in Maize 1297
  • References 1308
  • Xliii Biological Aspects of the Quantum Theory of Radiation Absorptions in Tissues 1311
  • References 1326
  • Subject Index 1331
  • Alphabetical List of Contributors 1343
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