Water stress in plants : proceedings of a Symposium held in Prague, September 30 - October 4, 1963

The study of water stress is one of the most interesting subjects in. the investigation of water relations in plants. From the theoretical point of view it is concerned with investigating the mechanisms of the distribution and movement of water in the plant organism and the way in which physiolo­ gical processes are influenced by water deficiency. From the practical point of view, water deficiency is a major factor limiting plant production. It has been progressively shown that water deficiency is not by far· only a factor in plant life in dry climates, that obvious wilting is not the first warning sign of water deficiency and that moderate water stress, caused by temporary negative water balance during the day, affects physiological ac­ tivity and decreases prodnction in the ecological conditions of the temperate zone. In addition, even general water deficiency is not today confined to arid or semi-arid zones and to the absolutely dry season of the year. The tremend­ ous consumption of water in our civilization has become today, even in the temperate zone, an important competitor with the plant cover. The study of water relations from the aspect of water stress is, therefore, important both theoretically and practically. I assume, therefore, that it was useful, important and interesting to meet in a symposium on water stress in plants and to discuss, as far as possible, in detail problems which are obviously among the main, whose solution would help plant physiology in increasing and improving plant production. Front Matter....Pages 1-17 Front Matter....Pages 19-19 The Problem of Water Outflow from Roots....Pages 21-29 The Relationship between the Sap Exudation Rate and the Exudation Lag....Pages 30-40 The Cell Sap Concentration in Maize Plants at Controlled Soil Moisture Stress....Pages 41-49 The Effect of Decrease in Soil Moisture on the Osmotic Values of Cell Sap in the Individual Organs of the Potato Plant....Pages 50-59 Front Matter....Pages 61-61 Some Investigations on Water Deficit and Transpiration Under Controlled Conditions....Pages 63-71 Water Relations of Plants in Experiments with Heavy Isotope O 18 ....Pages 72-80 State of Water in a Plant Cell, Mobility of Water and Factors which Determine it....Pages 81-88 Water Stress in Conifers During Winter....Pages 89-98 Serial Studies on the Hydration of Forest Plants....Pages 99-107 Water Relations of Some Steppe Plants Investigated by Means of the Reversibility of the Water Saturation Deficit....Pages 108-116 Changes in the Water Status in Plants Under Different External and Internal Conditions....Pages 117-127 The Effect of Relative Air Humidity on the Development of Water Saturation Deficit in the Cut Leaves of two Varieties of Barley....Pages 128-135 The Refractometric Method of Diagnosing Water Deficit in Plants....Pages 136-144 Front Matter....Pages 145-145 Stomata Reactivity in Leaves at Different Insertion Level During Wilting....Pages 147-154 Water Deficiency in the Process of Pathological Wilting....Pages 155-163 The Demonstration of a Porometer for Physiological and Ecological Investigations....Pages 164-166 The Water Relations of Tree Seedlings. V. Growth and Root Respiration in Relation to Osmotic Potential of the Root Medium....Pages 167-183 The Influence of Water Stress on the Relationship between Co 2 Uptake and Transpiration....Pages 184-194 The Influence of Decreasing Hydration Level on Photosynthetic Rate in the Thalli of the Hepatic Conocephallum Conicum....Pages 195-202 Water Saturation Deficit and Photosynthetic Rate as Related to Leaf age in the Wilting Plant....Pages 203-209 Front Matter....Pages 145-145 Relationship Between Chlorophyll Content and Photosynthetic Rate During the Vegetation Season in Maize Grown At Different Constant Soil Water Levels....Pages 210-218 Water Saturation Deficit of Intensely Photosynthesizing Leaf Tissue Well Supplied with Water....Pages 219-222 The Growth and Water Supply of Individual Organs of the Potato....Pages 223-227 The Influence of Soil Drought on the Vitality of Forest Plants....Pages 228-237 The Influence of Microelements on ATP Content in Plants in the Presence of Water Deficit and Under the Influence of High Temperatures....Pages 238-244 Front Matter....Pages 245-245 Changes in the Transpiration of Plants in the Course of the Day....Pages 247-256 The Moisture Consumption of Plants Described as a Hydrological Phenomenon....Pages 257-267 Water Relations of Some Species of Wormwood in Kazakhstan....Pages 268-275 Contribution to the Study of Varietal Differences in Water Relations in Spring Barley by Quantitative Analysis of Transpiration Curves....Pages 276-281 A Report on the Problem of the Water Economy of Oat Plants and of Regulating Transpiration by Treatment with Varying Amounts of Nitrogen....Pages 282-290 On the Problem of Cuvette-Climate (Preliminary Communication)....Pages 291-293 General Discussion....Pages 295-301 Discussion on Terminology and Linguistic Problems....Pages 303-308 Concluding Speech....Pages 309-311 Conclusion....Pages 312-312 Back Matter....Pages 313-322 Proceedings of a Symposium held in Prague, September 30-October 4, 1963