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Effects of NaCl on glycine-betaine and on aphids in cereal seedlings
Phytochemistry. Vol. 30, No. 6. pp. 1793.-1795. 1991 Printed in Great Britain.
EFFECTS
0031~9422/91 S3.00+0.00 C 1991Pcrgamon Press plc
OF NaCI ON GLYCINE-BETAINE CEREAL SEEDLINGS
FELKIANO
ARAYA,
OLGA
ABARCA,*
GUSTAVO
AND ON APHIDS
E. ZIMIGA+
Facultad de Ciencias Agropecuarias y Forestales, Universidad de ConcepcGn, Universidad de Santiago de Chile, Casilla 5659-2, Santiago, Chile; tFacultad Santiago-Chile
and
IN
LUIS J. CORCUERAt$
Casilla 537, Chillh-Chile; de Ciencias, Universidad
lFacultad de Ciencia, de Chile, Casilla 653,
(Received in revised firm 26 Ocroher 1990) Key Word Index- -Hordeurn; Triticum; Gramineae; stress.
Schizaphis graminwn;
greenbug;
aphids;
glycine-betaine;
salt
effect of NaCl on the aphid Schizaphis graminum was studied on seedlings and with artificial diets. Wheat and barley seedlings irrigated with saline Hoagland solution (@700 mM NaCl) accumulated ions in their leaves. Glycine-betaine, also accumulated in wheat and barley seedlings with increasing salt levels. The population growth rate of the aphid S. graminum in wheat decreased with the amount of salt accumulated by leaves. In barley, however, population growth rate of aphids reached a minimum at 50 mM NaCI, increasing at higher NaCl concentration. Survival of aphids feeding from artificial diets with NaCl decreased (LD,, = 65 mM). Glycine-betaine, however, increased both survival and reproduction in salt treated and untreated aphids. In addition, ingestion time of aphids feeding in artificial diets also decreased (ED,, = 105 mM). These results show that accumulation of NaCl by cereals is more deleterious to aphids in wheat than in barley. This could be partly explained by the higher glycinebetaine accumulation in barley leaves. Abstract-The
Ih’TRODUCTlON
The susceptibility of plants to insects may be affected by the presence of nutrients in the soil [I, 23. A positive correlation between growth rate of the aphid Myzus persicue (S) and potassium availability in the soil has been found in tobacco [3]. An increase in the growth rate of aphids in seedlings with a high nitrogen content has been observed in both greenhouse and in the field [4-83. Dactylis spicata, a perennial grass which grows in saline soils is poorly attacked by aphids [9, IO]. Salinity induces several metabolic changes in plants, such as accumulation proline and glycine-betaine [I 11. We have studied the effects of NaCl on aphids feeding on wheat and barley seedlings and with artificial diets, and on glycine-betaine accumulation in the leaves of these plants. RESULTS AND DISCUSSION
Eficts
of salt content in wheat and barley on aphids
Wheat seedlings cv Onda, irrigated with saline solutions accumulated Na’ and Cl- (Table I). The population growth rate of the aphid Schizaphis graminum decreased with salt concentration in the nutrient solution (Fig. 1). Rhopolosiphum padi showed a response similar to that of the greenbug (results not shown). Experiments with wheat and aphids were not done at salt concentrations higher than 200 mM because the seedlings were damaged. When different chloride salts were used (NH,Cl, CaCl,, KCI), leaves accumulated Cl- while the ZAuthor
to whom correspondence
should
be addressed. 1793
content of Na‘ remained constant. The relative growth rate of S. graminum decreased with the amount of Claccumulated by wheat leaves. Barley seedlings cv Aramir watered with less concentrated salt solutions, accumulated larger amounts of Na’ and Cl- than wheat (Table 1). The effect on relative population growth rate of aphids, however, was not as clear as in wheat seedlings (Fig. 1). At low NaCl concentration in the solution the population growth rate decreased drastically. The amount of Cl- accumulated by both species was different. At 50 mM NaCI, barley seedlings contained ca two-fold more Cl- than wheat. Barley seedlings under saline stress accumulate proline and glycine-betaine [I I]. The amount of glycine-betaine accumulated by barley seedlings was higher than by wheat (Fig. 2). It has been reported previously that glycine-betaine accumulation increases the susceptibility of barley cv F. Union against aphids [12]. An antagonistic effect on aphids between NaCl and glycine-betaine accumulation could be responsible for differences in population growth rate of aphids observed between barley and wheat. Thus, the bimodal response observed in barley (Fig. 1) could be the result of NaCl and glycinebetaine antagonism. Effects of NaCI on aphids fed with artijcial
diets
Nymphs of S. graminum were fed with artificial diets with different NaCl concentrations. Survival of aphids decreased with salt content in the diet (LDso of 65 mM at 48 hr) (Fig. 3). The LD,, for KCI was 10 mM. Addition of glycine-betaine decreased the effects of NaCl on survival of aphids. Reproduction of adult aphids was also de-
1194
F. ARAYA et al.
Table
1. Effect of saline treatment
on ion content
(mM)
Ca2 +
Mg2+
Ions (mmol kg. ’ dry wt) Na’ K’
Wheat 0 50 100 2000 300 400
103+3 82k4 88k2 99_+1 115*1 12424
247 f 23 192_+9 190*2 157+10 160+4 167,7
921+ 37 943 + 34 1060_+45 707+41 631+8 532+ 17
73+2 4855 17 807kll 1450+28 1940+ 75 2650 + 49
410* 1 1030+ 12 1400+11 205Ok 3 2850+11 403Ok9
189+4 104+6 102+2 80+1 90+2 92k6
1100+33 1070+ 10 1070+28 1010+9 830+ 13 614+ IO
170*3 1190+9 1440* 17 2050 k 43 221Ok6 2830 k 47
177+4 1810+5 2080+ 10 2520+ 5 2840+ 22 35OOk 25
Nail
Barley 0 50 100 200 300 400
95*4 7456 62k3 65*1 77+5 76+2
in wheat and barley leaves
Cl ..
Wheat and barley seedlings were irrigated with Hoagland nutrient solution as described in the Experimental. Each value represent the mean of 3 samples + I se. *Wheat seedlings irrigated with higher salt concentration showed more than 50% physiological damage.
I-
0
200
0
400
No Cl (mM) Fig. 1. Effect of NaCl concentration on relative population growth rate of the aphid S. graminum on wheat (0) and barley ((3) seedlings. Relative growth rate was calculated by r = In(N,/N,)/At. N, = final number of aphids, N, = initial number, At = time difference.
creased by NaCl in artificial diets (Fig. 4). Reproduction of both NaCl fed and non NaCl fed aphids increased when glycine-betaine was added to the diet. The feeding behaviour was also modified by the presence of NaCl in the diets. The total ingestion time decreased with NaCl content in diets (ED,,= 105 mM) (Fig. 5). The results reported here suggest that NaCl influences susceptibility of wheat and barley seedlings against aphids. There were some differences, however, between both plant species. Barley seedlings, which accumulate glycine-betaine were more tolerant to NaCl than wheat seedlings. In wheat, the physiological damage above 200 mM of NaCl was greater than in barley. Differences in the observed relative population growth rate between barley and wheat, may be due to physiological damage,
400
800
No Cl (mM) Fig. 2. Glycine
betaine accumulation in seven-day-old wheat seedlings under salt stress. Nutrient solutions with the indicated salt concentrations were used lo irrigate the seedlings.
(0) and barley(C)
glycine-betaine concentration, and/or salt accumulation. The NaCl LD,, values for aphids obtained in artificial diets, which are much below the salt concentration in leaves, suggest a role for NaCl accumulation in plant insect-interactions. Cultivars growing in saline soils may be more resistant to aphids. As glycine-betaine accumulation in salt resistant cultivars may increase reproduction of aphids, selection of varieties with alternative salt resistance mechanisms may be desirable. EXPERIMENTAL
Aphids. Individuals of S. graminum and R. padi were collected from colonies maintained on Hordeum distichum cv F. Union grown under continuous light in the laboratory at 25 + 3’.
Glycine-betaine
and aphids
1795
0 0
I30
300
NaCI (mM)
Fig. 3. Effect of NaCl and glycine-betaine on survival of aphids feeding on artificial diets. Each value is the mean of three samples of 10 aphids each after 48 hr of feeding.
Fig. 5. Effect of NaCl on ingestion time of aphids feeding on artificial diets. Feeding behaviour was electronically monitored over a period of 120 min. Each value is the mean of five adult aphids f I s.e.
probing behaviour of aphids on artificial diets was studied using electronic feeding monitors with AC batteries as power source. An electrode was attached to the back of the aphid and a second reference electrode was introduced in the diet. Wave-forms were interpreted as previously described [ 191.
REFERENCES
Fig. 4. Effect of NaCl and glycine-betaine on reproduction of aphids fed in artificial diets. Reproduction index is the amount of nymphs/adult aphids produced over a period of 72 hr. Each value is the mean of three samples of 10 aphids each.
Analyses of ions. Cations in soil and plant extracts were measured by flame spectrometry [13]. Ca”, Mg” and Na+ were determined by atomic absorption and K’ by atomic emission [13]. Cl- was determined by methods described previously [ 13, 141. Glycine-betainc and proline were extracted add quantified by procedures of refs [ 15, 163, respectively. PIanrs and salr treatments. Wheat and barley were grown in pots filled with sand and irrigated with H,O for 6 days. Sevenday-old seedlings were irrigated with a Hoagland nutrient soln modified according to ref. [17], with different NaCl concns. After 6 days of treatment, plants were infested with two apterous gyniparous aphids. The increase in the insect population was determined after 6 days. Three samples of 5 seedlings each were used for each treatment. Feeding ossoys. Aphid feeding assays were made in defined diets consisting of amino acids and 30% sucrose [18]. The
1. Haseman, L. (1946) .I. Econ. Enkmd. 39, 8. 2. Haseman, L. (1950) J. Econ. Entomol. 43, 399. A. W. and Harrison, F. P. (1968) J. Econ. 3. Wooldridge, Entomol. 61, 387. 4. Arant. F. S. and Jones,C. M.(1961)J. Econ. Entomol.44.121. 5. Coon, B. F. (1959) J. Econ. Entomol. 52, 624. 6. Branson, T. F. and Simpson, R. G. (1966) J. Econ. Entomol. 59,290. 7. Canillo, R. and Mundaca, N. (1976) Agro SW. 4, 15. 8. Mattson, W. J. (1980) Ann. Rev. Ecol. Sysl. 11, 1198. R. (1975) Ciencio Ino. Agrario 2, Il. 9. Honorato, F. (1987) M.Sc. Thesis. Facultad de Ciencias, 10. Araya, Universidad de Chile. 11. Wyn Jones, R. G. and Storey, R. (1976) Aust. J. P lanl Physiol. 5, 817. 26, 12. Zlifiiga, G. E. and Corcuera, L. J. (1987) Phytochemistry 367. 13. Piper, C. S. (1955) Soil and Plant A~ly~is. Interscience, New York. 14. Chadman, H. D. and Pratt, P. F. (1973) MPlodos de Andlisis pora Suelos, Plantas y Aguas, Trillas, Mexico. 15. Grieve, C. M. and Grattan. R. S. (1983) PI. Soil 70, 303. 16. Bates, L. M., Waldren, R. P. and Teare. I. D. (1973) PI. Sail 39, 205. 17. Epstein, E. (1972) Material Nutrition o/Plants: Principles and Perspectiws. John Wiley, New York. V. H. Pefia, G. F. Niemeyer, H. M. and 18. Argandofia, Corcuera, L. J. (1982) Phytochnistry 21, 1573. 19. Zliiiiga, G. E., Varanda, E. M. and Corcuera, L. J. (1988) Ent. Exp. Appl. 47, 161.
EFFECTS
0031~9422/91 S3.00+0.00 C 1991Pcrgamon Press plc
OF NaCI ON GLYCINE-BETAINE CEREAL SEEDLINGS
FELKIANO
ARAYA,
OLGA
ABARCA,*
GUSTAVO
AND ON APHIDS
E. ZIMIGA+
Facultad de Ciencias Agropecuarias y Forestales, Universidad de ConcepcGn, Universidad de Santiago de Chile, Casilla 5659-2, Santiago, Chile; tFacultad Santiago-Chile
and
IN
LUIS J. CORCUERAt$
Casilla 537, Chillh-Chile; de Ciencias, Universidad
lFacultad de Ciencia, de Chile, Casilla 653,
(Received in revised firm 26 Ocroher 1990) Key Word Index- -Hordeurn; Triticum; Gramineae; stress.
Schizaphis graminwn;
greenbug;
aphids;
glycine-betaine;
salt
effect of NaCl on the aphid Schizaphis graminum was studied on seedlings and with artificial diets. Wheat and barley seedlings irrigated with saline Hoagland solution (@700 mM NaCl) accumulated ions in their leaves. Glycine-betaine, also accumulated in wheat and barley seedlings with increasing salt levels. The population growth rate of the aphid S. graminum in wheat decreased with the amount of salt accumulated by leaves. In barley, however, population growth rate of aphids reached a minimum at 50 mM NaCI, increasing at higher NaCl concentration. Survival of aphids feeding from artificial diets with NaCl decreased (LD,, = 65 mM). Glycine-betaine, however, increased both survival and reproduction in salt treated and untreated aphids. In addition, ingestion time of aphids feeding in artificial diets also decreased (ED,, = 105 mM). These results show that accumulation of NaCl by cereals is more deleterious to aphids in wheat than in barley. This could be partly explained by the higher glycinebetaine accumulation in barley leaves. Abstract-The
Ih’TRODUCTlON
The susceptibility of plants to insects may be affected by the presence of nutrients in the soil [I, 23. A positive correlation between growth rate of the aphid Myzus persicue (S) and potassium availability in the soil has been found in tobacco [3]. An increase in the growth rate of aphids in seedlings with a high nitrogen content has been observed in both greenhouse and in the field [4-83. Dactylis spicata, a perennial grass which grows in saline soils is poorly attacked by aphids [9, IO]. Salinity induces several metabolic changes in plants, such as accumulation proline and glycine-betaine [I 11. We have studied the effects of NaCl on aphids feeding on wheat and barley seedlings and with artificial diets, and on glycine-betaine accumulation in the leaves of these plants. RESULTS AND DISCUSSION
Eficts
of salt content in wheat and barley on aphids
Wheat seedlings cv Onda, irrigated with saline solutions accumulated Na’ and Cl- (Table I). The population growth rate of the aphid Schizaphis graminum decreased with salt concentration in the nutrient solution (Fig. 1). Rhopolosiphum padi showed a response similar to that of the greenbug (results not shown). Experiments with wheat and aphids were not done at salt concentrations higher than 200 mM because the seedlings were damaged. When different chloride salts were used (NH,Cl, CaCl,, KCI), leaves accumulated Cl- while the ZAuthor
to whom correspondence
should
be addressed. 1793
content of Na‘ remained constant. The relative growth rate of S. graminum decreased with the amount of Claccumulated by wheat leaves. Barley seedlings cv Aramir watered with less concentrated salt solutions, accumulated larger amounts of Na’ and Cl- than wheat (Table 1). The effect on relative population growth rate of aphids, however, was not as clear as in wheat seedlings (Fig. 1). At low NaCl concentration in the solution the population growth rate decreased drastically. The amount of Cl- accumulated by both species was different. At 50 mM NaCI, barley seedlings contained ca two-fold more Cl- than wheat. Barley seedlings under saline stress accumulate proline and glycine-betaine [I I]. The amount of glycine-betaine accumulated by barley seedlings was higher than by wheat (Fig. 2). It has been reported previously that glycine-betaine accumulation increases the susceptibility of barley cv F. Union against aphids [12]. An antagonistic effect on aphids between NaCl and glycine-betaine accumulation could be responsible for differences in population growth rate of aphids observed between barley and wheat. Thus, the bimodal response observed in barley (Fig. 1) could be the result of NaCl and glycinebetaine antagonism. Effects of NaCI on aphids fed with artijcial
diets
Nymphs of S. graminum were fed with artificial diets with different NaCl concentrations. Survival of aphids decreased with salt content in the diet (LDso of 65 mM at 48 hr) (Fig. 3). The LD,, for KCI was 10 mM. Addition of glycine-betaine decreased the effects of NaCl on survival of aphids. Reproduction of adult aphids was also de-
1194
F. ARAYA et al.
Table
1. Effect of saline treatment
on ion content
(mM)
Ca2 +
Mg2+
Ions (mmol kg. ’ dry wt) Na’ K’
Wheat 0 50 100 2000 300 400
103+3 82k4 88k2 99_+1 115*1 12424
247 f 23 192_+9 190*2 157+10 160+4 167,7
921+ 37 943 + 34 1060_+45 707+41 631+8 532+ 17
73+2 4855 17 807kll 1450+28 1940+ 75 2650 + 49
410* 1 1030+ 12 1400+11 205Ok 3 2850+11 403Ok9
189+4 104+6 102+2 80+1 90+2 92k6
1100+33 1070+ 10 1070+28 1010+9 830+ 13 614+ IO
170*3 1190+9 1440* 17 2050 k 43 221Ok6 2830 k 47
177+4 1810+5 2080+ 10 2520+ 5 2840+ 22 35OOk 25
Nail
Barley 0 50 100 200 300 400
95*4 7456 62k3 65*1 77+5 76+2
in wheat and barley leaves
Cl ..
Wheat and barley seedlings were irrigated with Hoagland nutrient solution as described in the Experimental. Each value represent the mean of 3 samples + I se. *Wheat seedlings irrigated with higher salt concentration showed more than 50% physiological damage.
I-
0
200
0
400
No Cl (mM) Fig. 1. Effect of NaCl concentration on relative population growth rate of the aphid S. graminum on wheat (0) and barley ((3) seedlings. Relative growth rate was calculated by r = In(N,/N,)/At. N, = final number of aphids, N, = initial number, At = time difference.
creased by NaCl in artificial diets (Fig. 4). Reproduction of both NaCl fed and non NaCl fed aphids increased when glycine-betaine was added to the diet. The feeding behaviour was also modified by the presence of NaCl in the diets. The total ingestion time decreased with NaCl content in diets (ED,,= 105 mM) (Fig. 5). The results reported here suggest that NaCl influences susceptibility of wheat and barley seedlings against aphids. There were some differences, however, between both plant species. Barley seedlings, which accumulate glycine-betaine were more tolerant to NaCl than wheat seedlings. In wheat, the physiological damage above 200 mM of NaCl was greater than in barley. Differences in the observed relative population growth rate between barley and wheat, may be due to physiological damage,
400
800
No Cl (mM) Fig. 2. Glycine
betaine accumulation in seven-day-old wheat seedlings under salt stress. Nutrient solutions with the indicated salt concentrations were used lo irrigate the seedlings.
(0) and barley(C)
glycine-betaine concentration, and/or salt accumulation. The NaCl LD,, values for aphids obtained in artificial diets, which are much below the salt concentration in leaves, suggest a role for NaCl accumulation in plant insect-interactions. Cultivars growing in saline soils may be more resistant to aphids. As glycine-betaine accumulation in salt resistant cultivars may increase reproduction of aphids, selection of varieties with alternative salt resistance mechanisms may be desirable. EXPERIMENTAL
Aphids. Individuals of S. graminum and R. padi were collected from colonies maintained on Hordeum distichum cv F. Union grown under continuous light in the laboratory at 25 + 3’.
Glycine-betaine
and aphids
1795
0 0
I30
300
NaCI (mM)
Fig. 3. Effect of NaCl and glycine-betaine on survival of aphids feeding on artificial diets. Each value is the mean of three samples of 10 aphids each after 48 hr of feeding.
Fig. 5. Effect of NaCl on ingestion time of aphids feeding on artificial diets. Feeding behaviour was electronically monitored over a period of 120 min. Each value is the mean of five adult aphids f I s.e.
probing behaviour of aphids on artificial diets was studied using electronic feeding monitors with AC batteries as power source. An electrode was attached to the back of the aphid and a second reference electrode was introduced in the diet. Wave-forms were interpreted as previously described [ 191.
REFERENCES
Fig. 4. Effect of NaCl and glycine-betaine on reproduction of aphids fed in artificial diets. Reproduction index is the amount of nymphs/adult aphids produced over a period of 72 hr. Each value is the mean of three samples of 10 aphids each.
Analyses of ions. Cations in soil and plant extracts were measured by flame spectrometry [13]. Ca”, Mg” and Na+ were determined by atomic absorption and K’ by atomic emission [13]. Cl- was determined by methods described previously [ 13, 141. Glycine-betainc and proline were extracted add quantified by procedures of refs [ 15, 163, respectively. PIanrs and salr treatments. Wheat and barley were grown in pots filled with sand and irrigated with H,O for 6 days. Sevenday-old seedlings were irrigated with a Hoagland nutrient soln modified according to ref. [17], with different NaCl concns. After 6 days of treatment, plants were infested with two apterous gyniparous aphids. The increase in the insect population was determined after 6 days. Three samples of 5 seedlings each were used for each treatment. Feeding ossoys. Aphid feeding assays were made in defined diets consisting of amino acids and 30% sucrose [18]. The
1. Haseman, L. (1946) .I. Econ. Enkmd. 39, 8. 2. Haseman, L. (1950) J. Econ. Entomol. 43, 399. A. W. and Harrison, F. P. (1968) J. Econ. 3. Wooldridge, Entomol. 61, 387. 4. Arant. F. S. and Jones,C. M.(1961)J. Econ. Entomol.44.121. 5. Coon, B. F. (1959) J. Econ. Entomol. 52, 624. 6. Branson, T. F. and Simpson, R. G. (1966) J. Econ. Entomol. 59,290. 7. Canillo, R. and Mundaca, N. (1976) Agro SW. 4, 15. 8. Mattson, W. J. (1980) Ann. Rev. Ecol. Sysl. 11, 1198. R. (1975) Ciencio Ino. Agrario 2, Il. 9. Honorato, F. (1987) M.Sc. Thesis. Facultad de Ciencias, 10. Araya, Universidad de Chile. 11. Wyn Jones, R. G. and Storey, R. (1976) Aust. J. P lanl Physiol. 5, 817. 26, 12. Zlifiiga, G. E. and Corcuera, L. J. (1987) Phytochemistry 367. 13. Piper, C. S. (1955) Soil and Plant A~ly~is. Interscience, New York. 14. Chadman, H. D. and Pratt, P. F. (1973) MPlodos de Andlisis pora Suelos, Plantas y Aguas, Trillas, Mexico. 15. Grieve, C. M. and Grattan. R. S. (1983) PI. Soil 70, 303. 16. Bates, L. M., Waldren, R. P. and Teare. I. D. (1973) PI. Sail 39, 205. 17. Epstein, E. (1972) Material Nutrition o/Plants: Principles and Perspectiws. John Wiley, New York. V. H. Pefia, G. F. Niemeyer, H. M. and 18. Argandofia, Corcuera, L. J. (1982) Phytochnistry 21, 1573. 19. Zliiiiga, G. E., Varanda, E. M. and Corcuera, L. J. (1988) Ent. Exp. Appl. 47, 161.