Grafts et al. 



238 — 



Water in Plants 



hydrostatic, 44, 48 



osmotic {see Osmotic pressure) 



turgor {see Turgor pressure) 



vapor {see Vapor pressure) 

 Pressure-dehydration tests, 122 

 Pressure-membrane, moisture tension detn. with, 



151 

 Primary wall, 63 

 Primula, water deficit in, 201 

 Protease, water deficit and, 201 

 Protein, in plasma membranes, 78 



in protoplasmic structure, 66-67 



in vacuoles, 69 



metabolism, 139 



synthesis, 129 

 Proton, 13, 30 

 Protoplasm, coagulation of, 89 



constituents of, 61 



contractile nature of, 71, 126 



differential permeability of, 67 



fissures in, 119 



function in translocation, 174 



hydration of, 65-69, 71, 107, 122, 134-135, 

 145-146 



imbibition pressure of, 140 



pulsations of, 154 



streaming of, 68, 125 



structure of, 65-69 



structural viscosity of, 145 



volume of, in cells, 135 



water in, 65-69 

 Protoplasmic theory of translocation, 174, 175 

 Protoplast, active contraction of, 125, 140 

 Pulvinus, 140 



Pyridoxine, translocation of, 177 

 Pyrus tnalus, freez. pt. of sap, 120 

 PWP {see Permanent wilting percentage) 



Radioactive carbon, indicator of translocation, 



176 

 Radioactive tracers, in phloem, 168 



rate of water movement and, 169-170 

 Radiophosphorus, indicator of translocation, 175- 



176 

 Radish, water content of root, 62 

 Raffinose, mol. wt. detn. of, 87 

 Ranunculus fluitans, water movement in, 204 

 Raoult's law, 8, 14, 19, 34, 41, 48, 92 

 Reductase activity, water deficit and, 200 

 Relative humidity, 23, 24, 189, 190 

 Replasmolysis, 83-84, 114-116 

 Reserve carbohydrates, water deficit and, 202 

 Respiration, activity, 124, 132 



inhibitors of, 132 



rate of, and water uptake, 89, 129, 149-150 

 Rheum rhaponticum, PCD values in, 112 

 Rhodophyceae, 85 



Rhoeo discolor, adhesion pressure of leaf cells, 

 83 



OP of sap, 119 



plasmolytic studies of, 82, 87 

 Rihcs inertne, tensions in xylem of, 161 

 Riboflavin, translocation of, 177 

 Ricinus communis, internal leaf surface of, 195 

 Ring porous trees, rate of sap flow in, 156, 171 

 Rochea falcata, cuticular fissures in, 188 

 ROg {see Osmotic pressure by replasmolysis), 



116 

 Root pressure, as a non-osmotic force, 104, 150 



concentration of sap and, 104, 150 



method of DPD detn., 104 



subaqueous transpiration and, 203-204 

 Rytiphlaea iinctora, OP of sap of, 127 



Sagittaria, vacuolar contraction in, 125 

 Salt, {see also Solute) 



indicator of water movement, 168 



translocation of, 174 

 Salvinia auriculata, permeability of leaf cells, 80 

 Samhucus, gas in xylem of, 161 

 Sanchezia, rate of sap flow in, 169 



Sap, elastic expansion of, 157 



expressed, 126 



expression of, 90-91 



expression data, interpretation of, 117-122 



injury, 118 



protoplasmic, 70 



vacuolar, 70 

 Sap movement, methods for determining rate of, 

 168-170 



rate of, 167-172 

 Sargassum linifolium, sap of, 126 

 Saturation deficit, and dye movement in xylem, 



159 

 "Schlieren" method of DPD detn., 105, 165 

 Secondary wall, 63 

 Sedum album, OP of sap, 120 

 Sedum nicaense, vol. changes in, 84, 98 

 Sedum reflexum, OP of sap, 120 

 Sieve-tubes, structure and function, 174 



translocation in, 174-175 

 Simplified method of DPD detn., 98, 103-104 

 Sodium chlorate, translocation of, 157 

 Sodium chloride, as plasmolyzing subst., 83 



influence on transpiration, 198 

 Soil, OP of, and plant growth, 154 



saline, 153, 154 

 Soil moisture, availability, 152 



classification, 151 



DPD at field capacity, 152 



influence on absorption and growth, 148 



permanent wilting and, 152 



stress, 153 



tension, 151 

 Solanum, tonoplasts in, 78 



tuberosum, OP of sap, 120 

 water relations of, 127 

 {see also Potato) 

 Solidago virga aurea, transpiration of, 185 

 Solute absorption, water absorption and, 149, 



168 

 Solute accumulation, 79, 126, 138 



active water relations and, 138-139 

 Solute theory of osmosis, 52-54 

 Solutes, translocation, 174-177 

 Solution volume, 6, 47 

 Solutions, colligative properties, 18 



forces between atoms and molecules in, 20- 

 24 



hydration and, 26-30 



ideal, 18-19 



interrelations of properties of, 18-20 



mobility of ions in, 30-31 



molecular interaction and water binding, 24- 

 26 



non-ideal behavior of, 41-42 



osmotic pressure of {see Osmotic pressure) 



properties of, 18-31 

 Solvent, association of, 36 



diffusion pressure of, 55-57 



free energy of, 39 



theory of osmosis, 52-54 

 Sprays, effect on transpiration, 198-200 

 Spruce wood, water absorption by, 24 

 Spyridia filamentosa, cryoscopy of sap, 127 

 Squash, tension in, 166 



translocation in, 176 



wilting of, 173 

 Squirting cucumber, 107 

 Staminal hairs, 60, 85 

 Starch, conversion of, 202 

 Stem, contraction, 157 

 Stimulative plasmolysis, 124, 125, 145 

 Stomata, methods of measuring, 196-197 



number and distribution, 195-196 



regulation of transpiration by, 180, 197-198 



rhythmic fluctuations, 192 



wilting and, 160 



xeromorphism and, 200 

 Strip method of DPD detn., 103-104 

 Subaqueous transpiration, 203-205 

 Sucrose, effect of wilting of plants on, 202 



OP of solns. of, 32-39 



