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Effect of Putrescine on Growth and Photosynthetic Pigments of Broad Bean Plants Grown under Chloride Salinization Conditions1)
Biochem. Physiol. Pflanzen (BPP), Bd. 162, S. 203 -208 (1971)
Botany Laboratory - National Research Centre - Dokki, Cairo
Short Communication
Effect of Putrescine on Growth and Photosynthetic Pigments of Broad Bean Plants Grown under Chloride Salinization Conditions!) By NABlH I. ASHouR and ALIS T. THALOOTH (Received September 15, 1970)
Summary In sand culture the effect of putrescine as foliar spray on the growth and photosynthetic pigments of broad bean plants grown under both saline and nGn-s
Introduction STROGONOV (1962) and STROGONOV et al. (1970) reported that aliphatic diamines, putrescine and cadaverine, seemed to accumulate in broad bean and pea plants which affected with chloride salinization. It was suggested that accumulation of putrescine in 8alt-affected plants (STROGONOV et al. 1970) a3 well as in potassium-deficient plants (COLE:I1:AN and RICHARDS, 1956; SJliIITH and RICHARDS, 1962) seemed to cause the appearance of necrotic symptoms on the leaves. However, SHEVYAKOVA (1966) found that dipping the root of broad bean plants in diluted solution of putrescine or cadaverine stimulated plant growth. Nevertheless, more higher concentration of diamines were found to be toxic for plants. The effects of putrescine as foliar spray on growth and photosynthetic pigments of broad bean plants grown under both saline and non-saline conditions were investigated in this paper. 1) Dedicated to Prof. Dr. K.
~IoTHEs
on the Occasion of his 70th Birthday.
204
N. I. ASHouR and A. T. THALOOTH
Material and Methods Seeds of broad bean (Vicia faba L. var. Giza-2) were planted in pots No. 20 containing 3 kg acid-washed sand. The sand in the pots was irrigated with tap water till complete germination, then plants were thinned and two plants per pot were left. Half of the pots was irrigated with % strength complete Hoagland's nutrient solution (HEWITT, 1952), the second half was irrigated with the same nutrient solution plus 3000 ppm NaOl + CaOl (1: 1 w/w). The plants at age of 25 days of both saline and non-saline treatments were sprayed with 50, 100 and 200 ppm aqueous solution of putrescine dihydrochloride 1 ). The control plants received the same treatment but with distilled water. Every treatment had four replicates and each replicate contained five pots. After fifteen days from spraying treatments the plants were harvested and the stern length, Nr. of internodes and leaf area per plant were measured. Then the plants were washed with distilled water, divided into leaves, sterns and roots; oven-dried at 105°C, and its dry weight was recorded. The following analysis were made on the leaves: In the fresh leaves chlorophyll and carotenoids contents were determined spectrocolorimetrically using Wettstein's formula (WETTSTEIN, 1957) and chlorophyllase enzyme activity was estimated according to VOROBYOVA et al. (1963). Total-N determinations were made by a micro-kjeldahl procedure using copper-sulphate reduced iron catalyst.
Results
Under non-saline conditions (Table 1) it was found that spraying broad bean plants with putrescine solution was without significant effects on both stem length and number of internodes. Meanwhile, leaf area per plant was markedly stimulated, if the plants were sprayed with 100 ppm putrescine solution. In addition, slight non-significant increases in leaf area per plant were observed due to foliar application with 50 or 200 ppm putrescine solution. Table 1
Average stern length, number of internodes and leaf area of broad bean plant as affected by foliar spray with putrescine and salinity
Putrescine conc. (ppm)
Irrigation water Tap water
Saline water
Stern length (ern. )
Nr. of internodes
Leaf area cm 2 /plant
Stern length (ern. )
Nr. of internodes
Leaf area cm 2 /plant
0 50 100 200
35.6 35.3 37.9 36.8
8.2 8.6 9.2 8.7
258 269 313 280
31.6 37.2 37.6 37.3
7.8 8.7 8.9 8.4
222 249 237 324
L.S.D. at 5%
N. S.
N. S.
24
2.8
X. S.
28
1) Putrescine dihydrochloride w'as a gift from Prd. Dr. SCHUTTE, K. H., Inst. Plant Biochern., Halle-GDR, to whom the authers are greatly indepted.
205
Effect of Putrescine on Growth and Photosynthetic Pigments etc.
From the same table it can be also seen that, under chloride salinization conditions, spraying the plants with putrescine, generally, induced acceleration of stem elongation as compared with the control. Whereas, the number of internodes was not greatly affected with putrescine treatments. Leaf area per plant was greatly increased due to 200 ppm putrescine treatment. Table 2
Average dry weight of broad bean plant as affected by foliar spray with putrescine and salinity (calculated in gms/10 plants) Irrigation water
Putrescine cone. (ppm)
Leaves
Stems
Roots
Total
Leaves
Stems
Roots
Total
0 50 100 200
22.57 22.08 29.30 22.12
20.10 26.01 23.34 16.82
22.93 19.44 21.71 14.83
65.60 67.53 74.35 53.77
15.39 18.87 19.23 26.80
17.81 20.45 21.87 18.71
13.09 23.47 23.40 20.83
46.29 62.79 64.50 66.34
L.S.D. at 5%
·1.91
2.32
3.65
3.42
3.62
1.90
2.33
7.45
Tap water
Saline water
From Table 2 it is clear that under non-saline conditions spraying the plants with 100 ppm putrescine solution increased the dry weight of leaves; other concentrations of putrescine seemed to be without effect. Moreover, increases in the dry weight of stems were observed due to 50 and 100 ppm putrescine treatments, while 200 ppm putrescine decreased it as compared with the controL The root dry weight was not obviously changed, from the control, due to putrescine treatments, except with the heighest concentrations where it was reduced. The dry weight of whole plant showed an increase due to spraying with 100 ppm putrescine solution, whereas 200 ppm putrescine decreased it. Table 2 also s40ws that spraying salt-affected plants with 200 ppm putrescine solution caused an increase in the dry weight of leaves; more lower concentrations were less effective. The dry weights of stems and roots were increased due to 50 and 100 ppm putrescine treatments. Without exceptions, all putrescine treatments increased the dry weight of whole plants as compared with the unsprayed saltaffected plants. Table 3 shows that nitrogen concentration (mg-Njgm dry wt.) in the leaves was increased due to spraying the plants with 50 and 100 ppm putrescine solution, while its total content (mg-Njplant) showed a significant increase merIy with 100 ppm putrescine. The same table also shows that under saline conditions nitrogen concentration (mg-Njgm dry wt.) in the leaves was not significantly affected with 50 or 100 ppm putrescine treatments, while with 200 ppm putrescine its concentration was greatly
;'\. I.
206
ASHoeR
and
A.
T.
TIlALOOTH
Table 3 Average nitrogen content in the leaves of broad bean plants as affected by foliar spray with putrescine and salinity putrescine cone. (ppm) 0 50 100 200
L.S.D. at 5%
Irrigation water Saline water
Tap water mg X/gm dry wt.
mg N/plant
mg N/gm dry wt.
mg N/plant
37.74 40.26 39.43 41.13
85.08 88.89 115.53 90.99
40.22 41.54 40.43 34.77
61.90 78.39 77.54 83.18
1.58
6.12
2.42
7.31
depressed. The total nitrogen content in the leaves (mg-NJplant) of salt-affected plants, on the other hand, was increased due to putrescine treatments; the highest value was obtained with 200 ppm putrescine. Table 4 indicates that total chlorophyll content in the leaves, under non-saline conditions, was depressed after spraying the plants with 100 or 200 ppm putrescine. Carotenoids, on the other hand, was accumulated in the leaves due to spraying the plants with 100 ppm putrescine solution, while other concentrations were uneffective. Under the same irrigation conditions the activity of chlorophyllase enzyme in the leaves was greatly enhanced after spraying the plants with 100 or 200 ppm putrescine; however, 100 ppm putrescine treatment gave the highest value. From Table 3 it can be also seen that, under chloride salinization conditions, the total chlorophyll content in the leaves was decreased after spraying the plants with putrescine. Meanwhile, carotenoids content showed no obvious changes from the control due to putrescine treatments. The activity of chlorophyllase enzyme was enhanced with increasing the concentration of applied putrescine.
Discussion
Foliar spray of broad bean plants with 100 ppm putrescine solution stimulated plant growth. Spraying with more higher concentration of putrescine, on the contrary, inhibited plant growth. Similar effect was reported by SHEVYAKOVA (1966) when the roots of bean plants were treated with putrescine or cadaverine solutions. In this connection, it is worthwile to mcntion that putrescine in small concentrations was suggested to be a growth factor for certain micro organism (HERBST and SNELL, 1948). In addition, the regulating influence of diamines on nucleic acid metabolism may be also of great importance in this respect (TABOR et aI, 1961).
207
Effect of Putrescine on Growth and Photosynthetic Pigments etc.
It is interesting to note also that although salinity treatment greatly depressed the growth of the plants, yet spraying such plants with putrescine eliminated, to certain extent, the negative influence of salinity on plant growth. It seems that the activity of exogenous putrescine applied to salt-affected plants may be inhibited by other endogenous diamine, may be cadaverine (SNEATH, 1955), and/or by activated diaminooxidase enzyme (STROGONOV et al. 1970). The products of such reaction alongside the high content of nitrogen may stimulat plant growth (c. f. Tables 2 and 3). Table 4
Average photosynthetic pigments content and chlorophyllase activity in the leaves of broad bean plants as affected by foliar spray with putrescine and salinity Irrigation water
Putrescine conc. (ppm)
Saline water
Tap water 'Iotal Chlorophyll
ChloroCarotenoids phyllase activity
mgJdm 2 leaf area 0 2.09 0.82 50 1.79 0.78 100 1.59 0.95 200 1.66 0.86 L. S. D. at5 % 0.25 0.06
% 32.3 30.1 48.1 36.0 1.3
ChloroTotal Chlorophyll Carotenoids phyllase activity mgJdm 2 leaf area 2.31 0.86 1.72 0.84 1.68 0.87 1.56 0.92 0.42 N. S.
% 21.2 23.1 25.6 37.3 3.1
1) Percentage of the chlorophyll split during 1 hour incubation in the dark at room temperature.
The changes in chlorophyll content as well as chlorophyllase activity in the leaves due to putrescine treatments were more or less the same under saline and non-saline conditions. The observed enhancement of chlorophyllase enzyme activity due to putrescine treatment was inversely correllated with the decrease in chlorophyll content in the leaves. In this connection, the presence of high concentration of either exogenous or endogenous diamines in plants was reported to be accompaneid by partial bleaching of chlorophyll and consequently the appearance of necrotic symptoms on plant leaves (COLEMAN and RICHARDS, 1956; STROGONOV, 1962 and STROGONOV et al. 1970). From the obtained results it can be concluded that the effect of foliar spray with putrescine on the growth of broad bean plants would depend on its concentration; stimulatory at low concentration and inhibitory at high one. In addition spraying salt-aftected plants with putrescine resulted in overcoming some harmful effects of chloride salinity on plant growth. Nevertheless, further studies are needed to investigate the mechanism of such effect.
208
N. I. ASIIOUR and A. T. THALOOTH, Effect of Putrescine on Growth etc.
Literature COLEMAN, R. G., and RICHARDS, E. J., Ann. Bot., N. S., 20, 393-409 (1956). HERBST, E. J., and SNELL, E. E., J. BioI. Chern., 176, 989-991 (1948). HEWITT, E. J., Sand and Water Culture Methods used in the Study of Plant Nutrition. Commonwealth Agric. Bureaux, Farynham Royol, England 1952. : SHEVYAKOVA, N. 1., SOY. Plant Physiol., 13, 472-475 (1966). SMITH, T. A., and RICHARDS, F. J., Biochem. J., 84, 292-294 (1962). SNEATH, P. H. A., Nature, 175, 818-819 (1955). STROGONOV, B. P., Physiological Basis of Salt-Tolerance of Plants (under different type of soil salinization). Izd. Akad. ~auk, U.S.S.R., 248-257 (1962). - et aI., Structure and Function of Plant Cell in Saline Conditions. Izd. Akad. Nauk, U.S.S.R.,
224-244 (1970). TABOR, H., TABOR, C. W., and ROSENTHAL, M., Ann. Rev. Biochem. 30, 579-604 (1961). VOROBYOVA, L. M., PISTROVA, M. E., and KRASNOVSKY, A. A., SOY. Biochem. 28, 524-529
(1963). WETTSTEIN, D., Exptl. Cell Res., 12, 427 -438 (1957). Authors' address: Dr. NABIH 1. ASHOUR and ALIS T. THALOOTH, National Research Centre, Botany Department, Dokki, Cairo (Egypt.).
Verantwortlich !iir die Redaktion: Prof. Dr. K. Mothes, 401 Halle (Saale). Verlag: VEB Gustav Fischer Verlag, 69 Jena, Villengang 2, Telefon 24141, 24142. Alleinige Anzeigenannahme: DEWAG-Werbung Leipzig, 701 Leipzig, Bruhl 34-40, Telefon 29740, gultige Preisliste Nr.3. Satz und Druck: Druckerei "Magnus Poser", 69 Jena. - Veriiffentlicht unter der Lizenznummer 1067a des Presseamtes beim Vorsitzenden des Ministerrates der Deutschen Demokratischen Republik. Alle Rechte beim Verlag. Nachdruck (auch auszugsweise) nur mit Genehmigung des Verlages und des Verlassers sowie mit Angabe der Quelle gestattet. Printed in the German Democratic Republic.
Botany Laboratory - National Research Centre - Dokki, Cairo
Short Communication
Effect of Putrescine on Growth and Photosynthetic Pigments of Broad Bean Plants Grown under Chloride Salinization Conditions!) By NABlH I. ASHouR and ALIS T. THALOOTH (Received September 15, 1970)
Summary In sand culture the effect of putrescine as foliar spray on the growth and photosynthetic pigments of broad bean plants grown under both saline and nGn-s
Introduction STROGONOV (1962) and STROGONOV et al. (1970) reported that aliphatic diamines, putrescine and cadaverine, seemed to accumulate in broad bean and pea plants which affected with chloride salinization. It was suggested that accumulation of putrescine in 8alt-affected plants (STROGONOV et al. 1970) a3 well as in potassium-deficient plants (COLE:I1:AN and RICHARDS, 1956; SJliIITH and RICHARDS, 1962) seemed to cause the appearance of necrotic symptoms on the leaves. However, SHEVYAKOVA (1966) found that dipping the root of broad bean plants in diluted solution of putrescine or cadaverine stimulated plant growth. Nevertheless, more higher concentration of diamines were found to be toxic for plants. The effects of putrescine as foliar spray on growth and photosynthetic pigments of broad bean plants grown under both saline and non-saline conditions were investigated in this paper. 1) Dedicated to Prof. Dr. K.
~IoTHEs
on the Occasion of his 70th Birthday.
204
N. I. ASHouR and A. T. THALOOTH
Material and Methods Seeds of broad bean (Vicia faba L. var. Giza-2) were planted in pots No. 20 containing 3 kg acid-washed sand. The sand in the pots was irrigated with tap water till complete germination, then plants were thinned and two plants per pot were left. Half of the pots was irrigated with % strength complete Hoagland's nutrient solution (HEWITT, 1952), the second half was irrigated with the same nutrient solution plus 3000 ppm NaOl + CaOl (1: 1 w/w). The plants at age of 25 days of both saline and non-saline treatments were sprayed with 50, 100 and 200 ppm aqueous solution of putrescine dihydrochloride 1 ). The control plants received the same treatment but with distilled water. Every treatment had four replicates and each replicate contained five pots. After fifteen days from spraying treatments the plants were harvested and the stern length, Nr. of internodes and leaf area per plant were measured. Then the plants were washed with distilled water, divided into leaves, sterns and roots; oven-dried at 105°C, and its dry weight was recorded. The following analysis were made on the leaves: In the fresh leaves chlorophyll and carotenoids contents were determined spectrocolorimetrically using Wettstein's formula (WETTSTEIN, 1957) and chlorophyllase enzyme activity was estimated according to VOROBYOVA et al. (1963). Total-N determinations were made by a micro-kjeldahl procedure using copper-sulphate reduced iron catalyst.
Results
Under non-saline conditions (Table 1) it was found that spraying broad bean plants with putrescine solution was without significant effects on both stem length and number of internodes. Meanwhile, leaf area per plant was markedly stimulated, if the plants were sprayed with 100 ppm putrescine solution. In addition, slight non-significant increases in leaf area per plant were observed due to foliar application with 50 or 200 ppm putrescine solution. Table 1
Average stern length, number of internodes and leaf area of broad bean plant as affected by foliar spray with putrescine and salinity
Putrescine conc. (ppm)
Irrigation water Tap water
Saline water
Stern length (ern. )
Nr. of internodes
Leaf area cm 2 /plant
Stern length (ern. )
Nr. of internodes
Leaf area cm 2 /plant
0 50 100 200
35.6 35.3 37.9 36.8
8.2 8.6 9.2 8.7
258 269 313 280
31.6 37.2 37.6 37.3
7.8 8.7 8.9 8.4
222 249 237 324
L.S.D. at 5%
N. S.
N. S.
24
2.8
X. S.
28
1) Putrescine dihydrochloride w'as a gift from Prd. Dr. SCHUTTE, K. H., Inst. Plant Biochern., Halle-GDR, to whom the authers are greatly indepted.
205
Effect of Putrescine on Growth and Photosynthetic Pigments etc.
From the same table it can be also seen that, under chloride salinization conditions, spraying the plants with putrescine, generally, induced acceleration of stem elongation as compared with the control. Whereas, the number of internodes was not greatly affected with putrescine treatments. Leaf area per plant was greatly increased due to 200 ppm putrescine treatment. Table 2
Average dry weight of broad bean plant as affected by foliar spray with putrescine and salinity (calculated in gms/10 plants) Irrigation water
Putrescine cone. (ppm)
Leaves
Stems
Roots
Total
Leaves
Stems
Roots
Total
0 50 100 200
22.57 22.08 29.30 22.12
20.10 26.01 23.34 16.82
22.93 19.44 21.71 14.83
65.60 67.53 74.35 53.77
15.39 18.87 19.23 26.80
17.81 20.45 21.87 18.71
13.09 23.47 23.40 20.83
46.29 62.79 64.50 66.34
L.S.D. at 5%
·1.91
2.32
3.65
3.42
3.62
1.90
2.33
7.45
Tap water
Saline water
From Table 2 it is clear that under non-saline conditions spraying the plants with 100 ppm putrescine solution increased the dry weight of leaves; other concentrations of putrescine seemed to be without effect. Moreover, increases in the dry weight of stems were observed due to 50 and 100 ppm putrescine treatments, while 200 ppm putrescine decreased it as compared with the controL The root dry weight was not obviously changed, from the control, due to putrescine treatments, except with the heighest concentrations where it was reduced. The dry weight of whole plant showed an increase due to spraying with 100 ppm putrescine solution, whereas 200 ppm putrescine decreased it. Table 2 also s40ws that spraying salt-affected plants with 200 ppm putrescine solution caused an increase in the dry weight of leaves; more lower concentrations were less effective. The dry weights of stems and roots were increased due to 50 and 100 ppm putrescine treatments. Without exceptions, all putrescine treatments increased the dry weight of whole plants as compared with the unsprayed saltaffected plants. Table 3 shows that nitrogen concentration (mg-Njgm dry wt.) in the leaves was increased due to spraying the plants with 50 and 100 ppm putrescine solution, while its total content (mg-Njplant) showed a significant increase merIy with 100 ppm putrescine. The same table also shows that under saline conditions nitrogen concentration (mg-Njgm dry wt.) in the leaves was not significantly affected with 50 or 100 ppm putrescine treatments, while with 200 ppm putrescine its concentration was greatly
;'\. I.
206
ASHoeR
and
A.
T.
TIlALOOTH
Table 3 Average nitrogen content in the leaves of broad bean plants as affected by foliar spray with putrescine and salinity putrescine cone. (ppm) 0 50 100 200
L.S.D. at 5%
Irrigation water Saline water
Tap water mg X/gm dry wt.
mg N/plant
mg N/gm dry wt.
mg N/plant
37.74 40.26 39.43 41.13
85.08 88.89 115.53 90.99
40.22 41.54 40.43 34.77
61.90 78.39 77.54 83.18
1.58
6.12
2.42
7.31
depressed. The total nitrogen content in the leaves (mg-NJplant) of salt-affected plants, on the other hand, was increased due to putrescine treatments; the highest value was obtained with 200 ppm putrescine. Table 4 indicates that total chlorophyll content in the leaves, under non-saline conditions, was depressed after spraying the plants with 100 or 200 ppm putrescine. Carotenoids, on the other hand, was accumulated in the leaves due to spraying the plants with 100 ppm putrescine solution, while other concentrations were uneffective. Under the same irrigation conditions the activity of chlorophyllase enzyme in the leaves was greatly enhanced after spraying the plants with 100 or 200 ppm putrescine; however, 100 ppm putrescine treatment gave the highest value. From Table 3 it can be also seen that, under chloride salinization conditions, the total chlorophyll content in the leaves was decreased after spraying the plants with putrescine. Meanwhile, carotenoids content showed no obvious changes from the control due to putrescine treatments. The activity of chlorophyllase enzyme was enhanced with increasing the concentration of applied putrescine.
Discussion
Foliar spray of broad bean plants with 100 ppm putrescine solution stimulated plant growth. Spraying with more higher concentration of putrescine, on the contrary, inhibited plant growth. Similar effect was reported by SHEVYAKOVA (1966) when the roots of bean plants were treated with putrescine or cadaverine solutions. In this connection, it is worthwile to mcntion that putrescine in small concentrations was suggested to be a growth factor for certain micro organism (HERBST and SNELL, 1948). In addition, the regulating influence of diamines on nucleic acid metabolism may be also of great importance in this respect (TABOR et aI, 1961).
207
Effect of Putrescine on Growth and Photosynthetic Pigments etc.
It is interesting to note also that although salinity treatment greatly depressed the growth of the plants, yet spraying such plants with putrescine eliminated, to certain extent, the negative influence of salinity on plant growth. It seems that the activity of exogenous putrescine applied to salt-affected plants may be inhibited by other endogenous diamine, may be cadaverine (SNEATH, 1955), and/or by activated diaminooxidase enzyme (STROGONOV et al. 1970). The products of such reaction alongside the high content of nitrogen may stimulat plant growth (c. f. Tables 2 and 3). Table 4
Average photosynthetic pigments content and chlorophyllase activity in the leaves of broad bean plants as affected by foliar spray with putrescine and salinity Irrigation water
Putrescine conc. (ppm)
Saline water
Tap water 'Iotal Chlorophyll
ChloroCarotenoids phyllase activity
mgJdm 2 leaf area 0 2.09 0.82 50 1.79 0.78 100 1.59 0.95 200 1.66 0.86 L. S. D. at5 % 0.25 0.06
% 32.3 30.1 48.1 36.0 1.3
ChloroTotal Chlorophyll Carotenoids phyllase activity mgJdm 2 leaf area 2.31 0.86 1.72 0.84 1.68 0.87 1.56 0.92 0.42 N. S.
% 21.2 23.1 25.6 37.3 3.1
1) Percentage of the chlorophyll split during 1 hour incubation in the dark at room temperature.
The changes in chlorophyll content as well as chlorophyllase activity in the leaves due to putrescine treatments were more or less the same under saline and non-saline conditions. The observed enhancement of chlorophyllase enzyme activity due to putrescine treatment was inversely correllated with the decrease in chlorophyll content in the leaves. In this connection, the presence of high concentration of either exogenous or endogenous diamines in plants was reported to be accompaneid by partial bleaching of chlorophyll and consequently the appearance of necrotic symptoms on plant leaves (COLEMAN and RICHARDS, 1956; STROGONOV, 1962 and STROGONOV et al. 1970). From the obtained results it can be concluded that the effect of foliar spray with putrescine on the growth of broad bean plants would depend on its concentration; stimulatory at low concentration and inhibitory at high one. In addition spraying salt-aftected plants with putrescine resulted in overcoming some harmful effects of chloride salinity on plant growth. Nevertheless, further studies are needed to investigate the mechanism of such effect.
208
N. I. ASIIOUR and A. T. THALOOTH, Effect of Putrescine on Growth etc.
Literature COLEMAN, R. G., and RICHARDS, E. J., Ann. Bot., N. S., 20, 393-409 (1956). HERBST, E. J., and SNELL, E. E., J. BioI. Chern., 176, 989-991 (1948). HEWITT, E. J., Sand and Water Culture Methods used in the Study of Plant Nutrition. Commonwealth Agric. Bureaux, Farynham Royol, England 1952. : SHEVYAKOVA, N. 1., SOY. Plant Physiol., 13, 472-475 (1966). SMITH, T. A., and RICHARDS, F. J., Biochem. J., 84, 292-294 (1962). SNEATH, P. H. A., Nature, 175, 818-819 (1955). STROGONOV, B. P., Physiological Basis of Salt-Tolerance of Plants (under different type of soil salinization). Izd. Akad. ~auk, U.S.S.R., 248-257 (1962). - et aI., Structure and Function of Plant Cell in Saline Conditions. Izd. Akad. Nauk, U.S.S.R.,
224-244 (1970). TABOR, H., TABOR, C. W., and ROSENTHAL, M., Ann. Rev. Biochem. 30, 579-604 (1961). VOROBYOVA, L. M., PISTROVA, M. E., and KRASNOVSKY, A. A., SOY. Biochem. 28, 524-529
(1963). WETTSTEIN, D., Exptl. Cell Res., 12, 427 -438 (1957). Authors' address: Dr. NABIH 1. ASHOUR and ALIS T. THALOOTH, National Research Centre, Botany Department, Dokki, Cairo (Egypt.).
Verantwortlich !iir die Redaktion: Prof. Dr. K. Mothes, 401 Halle (Saale). Verlag: VEB Gustav Fischer Verlag, 69 Jena, Villengang 2, Telefon 24141, 24142. Alleinige Anzeigenannahme: DEWAG-Werbung Leipzig, 701 Leipzig, Bruhl 34-40, Telefon 29740, gultige Preisliste Nr.3. Satz und Druck: Druckerei "Magnus Poser", 69 Jena. - Veriiffentlicht unter der Lizenznummer 1067a des Presseamtes beim Vorsitzenden des Ministerrates der Deutschen Demokratischen Republik. Alle Rechte beim Verlag. Nachdruck (auch auszugsweise) nur mit Genehmigung des Verlages und des Verlassers sowie mit Angabe der Quelle gestattet. Printed in the German Democratic Republic.