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

Further information concerning the effect of ultra-violet radiation on anthocyanin development is given in another paper ( Arthur, Paper XXXV).


CONCLUDING REMARKS

In spite of the many publications on the subject, exact knowledge regarding the influence of ultra-violet radiation upon seed plants other than its destructive action is still to be ascertained. The interest in ultra-violet in recent years has been so widespread as to justify the accusation of some that the subject is a fad. It is to be hoped that the "fad" will not run its course before accurate information has been obtained. Needless to say, such information will not be forthcoming from experiments of short duration, carried out with a few plants under poorly controlled conditions such as have predominated in the work of the past.

Much of the present uncertainty of our knowledge of the effects of radiation upon plants rests upon the complexity of the problem itself. No other environmental factor is so variable or so difficult to control. The fact that plants require visible radiation for normal growth necessitates supplying them with this radiation. Sources of visible radiation usually contain also infra-red radiation. Consequently these factors must be considered and equalized in test cultures and controls when the effects of ultra-violet are to be studied. Total-radiation measurements, transmissions of screens, spectrograms of the radiation used, and the like, are in themselves insufficient to give a complete picture of the nature of the radiation reaching plants, although in many papers, even these variables are not given. Few, if any, authors have measured the total energy or the distribution of the energy in the ultra-violet to which results were attributed, to say nothing of the failure to equalize the radiant energy of other wave-lengths reaching the test plants as compared with the controls. While it is conceded that these measurements are difficult to make, it must also be admitted that so long as they remain unknown in an experiment the results cannot be attributed to ultra-violet any more than to any other operating variable.

In addition to the necessity of having a complete description of the radiation reaching plants it is no less important to know whether the plants or plant parts studied absorb selectively different portions of the spectrum and to what extent. Possible photochemical reactions in the plant may be greatly accelerated in a relatively narrow region of the spectrum that is strongly absorbed, whereas comparatively high intensities in a region that is feebly or not at all absorbed might be without effect.


REFERENCES

1. ANONYMOUS. "Kulturversuche unter Glassorten, die ultra-violetten Strahlen durchlassen, Brephosglas und Ultravitglas". Veroffentl. Landwirtschaftsk. Rheinprov. n. s. 18:49-50. 1930.

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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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