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Effect of Calcium Levels on Chlorophyll Synthesis in Peanut and Linseed Plants
,..
Biochem. Physiol. Pflanzen (BPP), Bd. 163, S. 443-44H (lH72) Botany Department, Allahabad University, Allahabad, India
Effect of Calcium Levels on Chlorophyll Synthesis in Peanut and Linseed Plants By R. N.
PAL
and M. M.
LALORAYA
With 3 figures (Received
~rarch
18, 1!172)
Summary The present study deals with the changes in different chlorophyll fractions yiz., protochlorophyll, l'hlorophyll-a and chlorophyll-b as influenced by calcium levels in peanut and linseed plants at different periods of growth. The plants were grown on acid washed silica sand and chlorophyll fractions of leaves were estimated spectrophotometrically. It has been shown that both high as well as low levels of calcium inhibit the chlorophyll formation in these two pi
Introduction
Both macro- and micronutrient deficiencies are known to cause chlorosis in higher plants and it is one of the most conspicuous symptoms of mineral deficiency (WALLACE 1961). However, very little is known regarding the mechanism by which lack of individual essential nutrient element cause its own characteristic pattern of chlorophyll inhibition. Lime induced chlorosis of plants is well known (PAL and LALORAY A 1968) and various theories have been proposed to explain the cause of chlorophyll insufficiency. Some elements e. g., nitrogen and magnesium are constituents of protochloroph~Tll and chlorophyll molecules, but how calcium and other elements are concerned in the synthesis of chloroph~TlI is still not very clear. The keto-acids metabolism as affected by calcium in peanut have already been reported in our previous communication (PAL et al. 1972). This paper describes the changes in protochloroph~Tll, chlorophyll-a and chlorophyll-b contents as influenced by different levels of ealcium, and at different periods of growth in peanut and linseed plants. Material and Methods The seeds of peanut (Arachis hypogaca) Var. Big Japan were obtained from Agricultural Research Station, Sabour, Bhagalpur and of linseed (Limlln usitntissimum) var. ~P (RR) 5 from
144
444
R. N. PAL and M. M. LALORAYA
Indian Agricultural Research Institute, New Delhi. Peanut seeds were soaked in distilled water for 48 hours before sowing them in glazed pots (12" X 12") containing acid washed silica sand as described elsewhere (PAL and LALORAYA 1967). Three plants were grown in each pot. In case of linseed, however, the seeds of approximately the same size were sorted out and sown directly in polythene pots (9" X 9") containing acid washed silica sand. After the plants were 15 days old, tbey were thinned to ten plants in each pot. Thirty pots were taken for each calcium treatment. ARNON and HOAGLAND'S (1940) nutrient solution was used in the present investigation. The different levels of calcium were made by either adding extra CaCl 2 in high calcium levels or by replacing Ca(NO a)2 by equimolar concentration of NaNO a which balanced the nitrogen level of the nutrient solution in case of low calcium levels. The plants were grown on following levels of calcium. A. Arachis hypogaea
Ca-l: Ca-2: Ca-3: Ca-4 (control): Ca-5: Ca-6: Ca-7: Ca-8:
0.1 M Calcium chloride in addition to Ca(NOah ) which is present in the normal control 0.03 M 0.01 M solution 0.003 M Ca(NO a)2 0,001 M Ca(NO a)2 + 0.004 M NaNO a 0.0003 M Ca(NO a)2 + 0.0054 M NaNO a 0.0001 M Ca(NOah + 0.0058 M NaNO a Minus calcium + 0.006 M NaNO a
B. Linurn usitatissirnurn
Ca-l: Ca-2: Ca-3 (control): Ca-4: Ca-5 : Ca-6:
0.1 M Calcium chloride in addition to Ca(NO a)2 } 0.03 M which is present in the normal control solution 0.003 M Ca(NO a)2 0.001 M Ca(NOah + 0.004 M NaNO a 0.0001 M Ca(NOah + 0.0058 M NaNO a Minus calcium + 0.006 M NaNOa
The plants were analysed for different chlorophyll fractions at four growth intervals viz. 25, 40, 55 and 70 days of growth in case of peanut and at 45, 60, 75 and 90 days of growth in case of linseed plants. The protochlorophyll, chlorophyll-a and chlorophyll-b content of leaves were estimated spectrophotometrically by the procedure of Comar and ZSCHEILE (1942). The mg. pigment content was calculated from the absorption coefficient of protochlorophyll, chlmophyll-a and chlorophyll-b at 623, 662 and 644 m,u respectively (SMITH and BENITEZ 1955).
Results
Figs. 1 to 3 show the results. It will be observed that all the three chlorophyll fractions viz., proto chlorophyll, chlorophyll-a and chlorophyll-b decrease at both low and high levels of calcium in peanut plants. Themost marked changes are, however, observed in chlorophyll-a content. The changes in chlorophyll-b although showing the same overall pattern, are less marked than chlorophyll-a. The ratio of chlorophyll alb does not change very much with the calcium levels, but a change in the ratio is observed from the first harvest to the fourth harvest. At the first harvest this
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0 10-"
70- 3
70- 2
0·0
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I
o
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70-t,.
10-3
70- 2
70-'
(/'10LARJ
Fig. 1. Changes in chlorophyll-a and chlorophyll-b at different levels of calcium in peanut (Arachis hypogaea) at different harvests. D = Days.
Arachis ~YEEgaeC1
o·o't
0'035
0·03
D&S
~
O'OZ
o
iO- f
(/'10LAR)
Fig. 2. Changes in proto chlorophyll at different levels of calcium in peanut and linseed plants at different harvests.
r
itli
£
446
R. X. P.u and M. !VI.
L.\LORA YA
0·8
090D
0·09 0·08
I
o
I
10-"
10-J
(1'10LAR)
Fig. :l. Changes in chlorophyll-a and chlorophyll-b at different levels of calcium in linseed (Linurn usitatissim1lm) at different harvests.
ratio is low i. e., about 1: 5 (fig. 1), which increases 3-4 in subsequent harvests. At the fourth harvest the ratio of chl.-a/chl.-b ranges from 4-6.5. This increase in ratio is due to increase in chlorophyll-a content from first harvest to the fourth harvest and a decline in chlorophyll-b content. The protochlorophyll content in peanut leaves is low. The ratio of chlorophyll-a/ proto chlorophyll varies between 8-12. The changes in protochlorophyll, however, closely parallels changes in chlorophyll-a content (fig. 2). A decrease in proto chi orophyll in both calcium deficient and high calcium plants are observed. In case of linseed plants, the results are almost similar to those reported for peanut (fig. 2 and 3). A decrease in different fractions of chlorophylls viz., chlorophylla, chlorophyll-b and protochlorophyll are observed both at low as well as high levels of calcium. Chlorophyll-a exhibited most marked changes, while changes in chlorophyll-b differed somewhat from one harvest to the other. It will be interesting here to mention that both high as well as low levels of calcium inhibit the vegetative growth of peanut and linseed plants (PAL 1970) and these growth effects are best correlated with the observed changes in different chlorophyll fractions viz., protochlorophyll, chlorophyll-a and chlorophyll-b.
t
Effeet of CaleilLlll Leyels on Chloropllyll Synthesis etc.
447
Discussion
The results presented here clearly show that calcium supply exerts a definitive control on the chlorophyll formation in both peanut and linseed plants. The smoothness of the curve and the uniformity shown at differcnt harvests indicates the normalcy of the effect. Absence of any particular mineral from the ionic composition of a nutrient solution may exert inhibitory effect on specific metabolic processes because of several reasons. a) The mineral may be directly required for the synthesis of a metabolite either as an enzyme co-factor or being itself a part of the molecule. b) It may act indirectly by interferring with the uptake of other essential ions required for the process, when the mineral itself may have no direct role in the process. Calcium is not known to be directly required at any step in enzymic reactions leading to chlorophyll synthesis. It is known, however, to control and modify the uptake of nitrogen and magnesium ions, two important components of the chlorophyll from the ionic environment. About 10 %1 of the magnesium present in plants is located in the chloroplasts, with magnesium comprising about 2.7 %ofthe chlorophyll molecule. VIETS (1944) showed that the presence of calcium in the nutrient media affects the uptake of other ions and MOORE et a1. (1961) showed that Ca++ inhibits the uptake of magnesium ions. Magnesium being a very important component of the chlorophyll molecule, it is possible that the inhibition of chlorophylls observed at high calcium levels may be due to its depressing effect on the uptake of magnesium. Several other trace clements such as iron, copper and zinc appear to be involved in the enzymatic steps of chlorophyll synthesis. The lime-induced chlorosis is thought to be associated with impeded iron metabolism of plants grown on calcareous soils. The iron content of the chlorotic leaves, in the lime induced chlorosis and the normal leaves being the same (OSERKOWSKY 1933), and the observation that these chlorotic leaves turned green when sprayed with solution of iron compounds, led to the suggestion that iron was present in the leaves in inactive form. Since iron is not known to be constituent of the chlorophyll molecule, it is assumed that iron acts in a catalytic manner in chlorophyll formation, presumably acting as a cofactor in some enz!Tmic reactions. Calcium deficiency on the other hand, results in the reduced uptake and assimilation of nitrate nitrogen (BURRELL 1926; BURSTROM 1954; NIGHTINGALE et a1. 1931) and this ma!' account for the inhibitory effect of calcium levels on chlorophyll synthesis. Calcium is also essential for structural and functional integrity of cellular membranes (MARINOS 1962) and its promotive effects on the uptake of potassium (EpSTEIN 1961; HIRATA and MITSUI 1963; JACOBSON et a1. 1960; KHAN and HANSON 1957) and phosphate (LEGGETT et a1. 1965; TANADA 1955) is well known. Therefore,
, .,/48
R N. PAL and M. M. LALORAYA
deficiency of calcium would result in reduced uptake of these ions which participate in important biochemical reactions leading to growth and formation of chlorophylls. Calcium levels would thus seem to exert its effect on chlorophyll formation through its control on the uptake of minerals essential for chlorophyll biosynthesis and such general effects as in controlling membrane formation and hydration state of the membranes and the cytoplasm. It would also appear that the observed inhibitory effect of calcium deficiency and of high level of calcium, is probably mediated by very different mechanisms.
Acknowledgement This research was supported by the grant from U.S. PL-480 scheme No. JiG-In. 232, which is thankfully acknowledged.
Literature ARNON, D. 1., and HOAGLAND, D. R, Crop production in soil with special reference to factors influencing yield and absorption of inorganic riutrients. Soil Sci. 50, 463 (1940). BURRELL, R C., Effects of certain deficiencies on nitrogen metabolism of plants. Bot. Gaz. 82, 320 (1926). BURSTROM, H., Studies on growth and metabolism of roots. X-Investigations of the calcium effect. Physiol. Plant. 7,332 (1954). COMAR, C. L., and ZSCHEILE, F. P., Analysis of plant extracts for chlorophylls a and by photoelectric spectrophotometric method. Plant Physiol. 17, 198 (1942). EpSTEIN, E., The essential role of calcium in selective cation transport by plant cells. Plant Physiol. 36, 437 (1961). HIRATA, H., and MrrsUI, S., Role of calcium in potassium uptake by plant roots. Plant and Cell Physiol. 6, 699 (1963). JACOBSON, L., MOORE, D. P., and HANNAPEL, R J., Role of calcium in absorption of monovalent cations. Plant Physiol. 35, 352 (1960). KAHN, J. S., and HANSON, J. R, The effect of calcium on potassium accumulation in corn and soybean roots. Plant Physiol. 32, 312 (1957). LEGGETT, J. E., GALLOWAY, R A., and GAUCH, H. G., Calcium activation of orthophosphate absorption by barley roots. Plant Physiol. 40, 897 (1965). MARINOS, N. G., Studies on submicroscopic aspects of mineral deficiencies. I-Calcium deficiency in shoot apex of barley. Amer. Jour. Bot. 49, 834 (1962). MOORE, D. P., OVERSTREET, R, and JACOBSON, L., Uptake of magnesium and its inactivation with calcium in excised barley roots. Plant Physiol. 36, 290 (1961). NIGHTINGALE, G. '1'., ADDOMS, R M., ROBBINS, W. R, and SCHERMERHORN, I~. G., Effects of calcium deficiency on nitrate absorption and on metabolism in tomato. Plant Physiol. 6, 605 (1931). OSERKOWSKY, J. Quantitative relation between chlorophyll and iron in green and chlorotic pear leaves. Plant Physiol. 8, 449 (1933). PAL, R N., and LALORAYA, M..M., Calcium-Sodium interaction in the pod development of the peanut, Arachis hypogaea L. Experientia 23, 382 (1967).
I
f
Effect of Calcium Levels on Chlorophyll Synthesis etc.
449
Role of calcium in growth, metabolic activities and uptake of other ions in plants - A Review. Allahabad Univ. Studies, Botany section, 1-37 (1968). Studies on effects of calcium on growth and metabolic activities of certain crop plants. Ph. D. Thesis, Allahabad University, Allahabad, India (1970). - KAUSHIK, D. D., and LALORAYA, M. M., Effects of calcium on the keto-acids metabolism of peanut, Arachis hypogaea. Z. Pflanzenphysiol. 66, 167 (1972). SMITH, J. H. C., and BENITEZ, A., Chlorophylls: Analysis in plant materials. In: Modern Methods of Plant Analysis, Vol. IV. Eds. PAECH, K., and TRACEY, M. V. Springer Verlag, Germany, 142-192 (1955). T i1cNADA, T., Effect of ribonuclease on salt absorption by excised mung bean roots. Plant Physiol. 31, 251 (1956). VIETS, F. G., Calcium and other polyvalent cations as accelerators of ion accumulation by excised barley roots. Plant Physiol. 19, 466 (1944). WALLACE, T., The diagnosis of mineral deficiencies in plants by visual symptoms. Published by Her Majesty's Stationery Office, London. Third Ed. (1961). Authors' address: Dr. R. N. PAL, Regional Fruit Research Station, Punjab Agricultural University, Abohar, Punjab, and Dr. M. M. LALORAYA, Botany Department, University School of Sciences, Gujarat University, Ahmedabad-9, Gujarat (India).
Biochem. Physiol. Pflanzen (BPP), Bd. 163, S. 443-44H (lH72) Botany Department, Allahabad University, Allahabad, India
Effect of Calcium Levels on Chlorophyll Synthesis in Peanut and Linseed Plants By R. N.
PAL
and M. M.
LALORAYA
With 3 figures (Received
~rarch
18, 1!172)
Summary The present study deals with the changes in different chlorophyll fractions yiz., protochlorophyll, l'hlorophyll-a and chlorophyll-b as influenced by calcium levels in peanut and linseed plants at different periods of growth. The plants were grown on acid washed silica sand and chlorophyll fractions of leaves were estimated spectrophotometrically. It has been shown that both high as well as low levels of calcium inhibit the chlorophyll formation in these two pi
Introduction
Both macro- and micronutrient deficiencies are known to cause chlorosis in higher plants and it is one of the most conspicuous symptoms of mineral deficiency (WALLACE 1961). However, very little is known regarding the mechanism by which lack of individual essential nutrient element cause its own characteristic pattern of chlorophyll inhibition. Lime induced chlorosis of plants is well known (PAL and LALORAY A 1968) and various theories have been proposed to explain the cause of chlorophyll insufficiency. Some elements e. g., nitrogen and magnesium are constituents of protochloroph~Tll and chlorophyll molecules, but how calcium and other elements are concerned in the synthesis of chloroph~TlI is still not very clear. The keto-acids metabolism as affected by calcium in peanut have already been reported in our previous communication (PAL et al. 1972). This paper describes the changes in protochloroph~Tll, chlorophyll-a and chlorophyll-b contents as influenced by different levels of ealcium, and at different periods of growth in peanut and linseed plants. Material and Methods The seeds of peanut (Arachis hypogaca) Var. Big Japan were obtained from Agricultural Research Station, Sabour, Bhagalpur and of linseed (Limlln usitntissimum) var. ~P (RR) 5 from
144
444
R. N. PAL and M. M. LALORAYA
Indian Agricultural Research Institute, New Delhi. Peanut seeds were soaked in distilled water for 48 hours before sowing them in glazed pots (12" X 12") containing acid washed silica sand as described elsewhere (PAL and LALORAYA 1967). Three plants were grown in each pot. In case of linseed, however, the seeds of approximately the same size were sorted out and sown directly in polythene pots (9" X 9") containing acid washed silica sand. After the plants were 15 days old, tbey were thinned to ten plants in each pot. Thirty pots were taken for each calcium treatment. ARNON and HOAGLAND'S (1940) nutrient solution was used in the present investigation. The different levels of calcium were made by either adding extra CaCl 2 in high calcium levels or by replacing Ca(NO a)2 by equimolar concentration of NaNO a which balanced the nitrogen level of the nutrient solution in case of low calcium levels. The plants were grown on following levels of calcium. A. Arachis hypogaea
Ca-l: Ca-2: Ca-3: Ca-4 (control): Ca-5: Ca-6: Ca-7: Ca-8:
0.1 M Calcium chloride in addition to Ca(NOah ) which is present in the normal control 0.03 M 0.01 M solution 0.003 M Ca(NO a)2 0,001 M Ca(NO a)2 + 0.004 M NaNO a 0.0003 M Ca(NO a)2 + 0.0054 M NaNO a 0.0001 M Ca(NOah + 0.0058 M NaNO a Minus calcium + 0.006 M NaNO a
B. Linurn usitatissirnurn
Ca-l: Ca-2: Ca-3 (control): Ca-4: Ca-5 : Ca-6:
0.1 M Calcium chloride in addition to Ca(NO a)2 } 0.03 M which is present in the normal control solution 0.003 M Ca(NO a)2 0.001 M Ca(NOah + 0.004 M NaNO a 0.0001 M Ca(NOah + 0.0058 M NaNO a Minus calcium + 0.006 M NaNOa
The plants were analysed for different chlorophyll fractions at four growth intervals viz. 25, 40, 55 and 70 days of growth in case of peanut and at 45, 60, 75 and 90 days of growth in case of linseed plants. The protochlorophyll, chlorophyll-a and chlorophyll-b content of leaves were estimated spectrophotometrically by the procedure of Comar and ZSCHEILE (1942). The mg. pigment content was calculated from the absorption coefficient of protochlorophyll, chlmophyll-a and chlorophyll-b at 623, 662 and 644 m,u respectively (SMITH and BENITEZ 1955).
Results
Figs. 1 to 3 show the results. It will be observed that all the three chlorophyll fractions viz., proto chlorophyll, chlorophyll-a and chlorophyll-b decrease at both low and high levels of calcium in peanut plants. Themost marked changes are, however, observed in chlorophyll-a content. The changes in chlorophyll-b although showing the same overall pattern, are less marked than chlorophyll-a. The ratio of chlorophyll alb does not change very much with the calcium levels, but a change in the ratio is observed from the first harvest to the fourth harvest. At the first harvest this
,. :::: ~ "t 'C2
'-> c....'->
'-> '-> '-
I
t::I
\Ii'"
0'9
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0'8
tl ~
tl tl
Ql
~ ~
~ tl(l
x
~
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<0 "-<0
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Chloro/!!lyll - a O·It
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0·7
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0·8
~
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· .... 0
x'x --0700
--xSSo
...11,,0/
x_xsso
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-----....L
I I
0 10-"
70- 3
70- 2
0·0
70- 1
C A L C
I
o
UN
70-t,.
10-3
70- 2
70-'
(/'10LARJ
Fig. 1. Changes in chlorophyll-a and chlorophyll-b at different levels of calcium in peanut (Arachis hypogaea) at different harvests. D = Days.
Arachis ~YEEgaeC1
o·o't
0'035
0·03
D&S
~
O'OZ
o
iO- f
(/'10LAR)
Fig. 2. Changes in proto chlorophyll at different levels of calcium in peanut and linseed plants at different harvests.
r
itli
£
446
R. X. P.u and M. !VI.
L.\LORA YA
0·8
090D
0·09 0·08
I
o
I
10-"
10-J
(1'10LAR)
Fig. :l. Changes in chlorophyll-a and chlorophyll-b at different levels of calcium in linseed (Linurn usitatissim1lm) at different harvests.
ratio is low i. e., about 1: 5 (fig. 1), which increases 3-4 in subsequent harvests. At the fourth harvest the ratio of chl.-a/chl.-b ranges from 4-6.5. This increase in ratio is due to increase in chlorophyll-a content from first harvest to the fourth harvest and a decline in chlorophyll-b content. The protochlorophyll content in peanut leaves is low. The ratio of chlorophyll-a/ proto chlorophyll varies between 8-12. The changes in protochlorophyll, however, closely parallels changes in chlorophyll-a content (fig. 2). A decrease in proto chi orophyll in both calcium deficient and high calcium plants are observed. In case of linseed plants, the results are almost similar to those reported for peanut (fig. 2 and 3). A decrease in different fractions of chlorophylls viz., chlorophylla, chlorophyll-b and protochlorophyll are observed both at low as well as high levels of calcium. Chlorophyll-a exhibited most marked changes, while changes in chlorophyll-b differed somewhat from one harvest to the other. It will be interesting here to mention that both high as well as low levels of calcium inhibit the vegetative growth of peanut and linseed plants (PAL 1970) and these growth effects are best correlated with the observed changes in different chlorophyll fractions viz., protochlorophyll, chlorophyll-a and chlorophyll-b.
t
Effeet of CaleilLlll Leyels on Chloropllyll Synthesis etc.
447
Discussion
The results presented here clearly show that calcium supply exerts a definitive control on the chlorophyll formation in both peanut and linseed plants. The smoothness of the curve and the uniformity shown at differcnt harvests indicates the normalcy of the effect. Absence of any particular mineral from the ionic composition of a nutrient solution may exert inhibitory effect on specific metabolic processes because of several reasons. a) The mineral may be directly required for the synthesis of a metabolite either as an enzyme co-factor or being itself a part of the molecule. b) It may act indirectly by interferring with the uptake of other essential ions required for the process, when the mineral itself may have no direct role in the process. Calcium is not known to be directly required at any step in enzymic reactions leading to chlorophyll synthesis. It is known, however, to control and modify the uptake of nitrogen and magnesium ions, two important components of the chlorophyll from the ionic environment. About 10 %1 of the magnesium present in plants is located in the chloroplasts, with magnesium comprising about 2.7 %ofthe chlorophyll molecule. VIETS (1944) showed that the presence of calcium in the nutrient media affects the uptake of other ions and MOORE et a1. (1961) showed that Ca++ inhibits the uptake of magnesium ions. Magnesium being a very important component of the chlorophyll molecule, it is possible that the inhibition of chlorophylls observed at high calcium levels may be due to its depressing effect on the uptake of magnesium. Several other trace clements such as iron, copper and zinc appear to be involved in the enzymatic steps of chlorophyll synthesis. The lime-induced chlorosis is thought to be associated with impeded iron metabolism of plants grown on calcareous soils. The iron content of the chlorotic leaves, in the lime induced chlorosis and the normal leaves being the same (OSERKOWSKY 1933), and the observation that these chlorotic leaves turned green when sprayed with solution of iron compounds, led to the suggestion that iron was present in the leaves in inactive form. Since iron is not known to be constituent of the chlorophyll molecule, it is assumed that iron acts in a catalytic manner in chlorophyll formation, presumably acting as a cofactor in some enz!Tmic reactions. Calcium deficiency on the other hand, results in the reduced uptake and assimilation of nitrate nitrogen (BURRELL 1926; BURSTROM 1954; NIGHTINGALE et a1. 1931) and this ma!' account for the inhibitory effect of calcium levels on chlorophyll synthesis. Calcium is also essential for structural and functional integrity of cellular membranes (MARINOS 1962) and its promotive effects on the uptake of potassium (EpSTEIN 1961; HIRATA and MITSUI 1963; JACOBSON et a1. 1960; KHAN and HANSON 1957) and phosphate (LEGGETT et a1. 1965; TANADA 1955) is well known. Therefore,
, .,/48
R N. PAL and M. M. LALORAYA
deficiency of calcium would result in reduced uptake of these ions which participate in important biochemical reactions leading to growth and formation of chlorophylls. Calcium levels would thus seem to exert its effect on chlorophyll formation through its control on the uptake of minerals essential for chlorophyll biosynthesis and such general effects as in controlling membrane formation and hydration state of the membranes and the cytoplasm. It would also appear that the observed inhibitory effect of calcium deficiency and of high level of calcium, is probably mediated by very different mechanisms.
Acknowledgement This research was supported by the grant from U.S. PL-480 scheme No. JiG-In. 232, which is thankfully acknowledged.
Literature ARNON, D. 1., and HOAGLAND, D. R, Crop production in soil with special reference to factors influencing yield and absorption of inorganic riutrients. Soil Sci. 50, 463 (1940). BURRELL, R C., Effects of certain deficiencies on nitrogen metabolism of plants. Bot. Gaz. 82, 320 (1926). BURSTROM, H., Studies on growth and metabolism of roots. X-Investigations of the calcium effect. Physiol. Plant. 7,332 (1954). COMAR, C. L., and ZSCHEILE, F. P., Analysis of plant extracts for chlorophylls a and by photoelectric spectrophotometric method. Plant Physiol. 17, 198 (1942). EpSTEIN, E., The essential role of calcium in selective cation transport by plant cells. Plant Physiol. 36, 437 (1961). HIRATA, H., and MrrsUI, S., Role of calcium in potassium uptake by plant roots. Plant and Cell Physiol. 6, 699 (1963). JACOBSON, L., MOORE, D. P., and HANNAPEL, R J., Role of calcium in absorption of monovalent cations. Plant Physiol. 35, 352 (1960). KAHN, J. S., and HANSON, J. R, The effect of calcium on potassium accumulation in corn and soybean roots. Plant Physiol. 32, 312 (1957). LEGGETT, J. E., GALLOWAY, R A., and GAUCH, H. G., Calcium activation of orthophosphate absorption by barley roots. Plant Physiol. 40, 897 (1965). MARINOS, N. G., Studies on submicroscopic aspects of mineral deficiencies. I-Calcium deficiency in shoot apex of barley. Amer. Jour. Bot. 49, 834 (1962). MOORE, D. P., OVERSTREET, R, and JACOBSON, L., Uptake of magnesium and its inactivation with calcium in excised barley roots. Plant Physiol. 36, 290 (1961). NIGHTINGALE, G. '1'., ADDOMS, R M., ROBBINS, W. R, and SCHERMERHORN, I~. G., Effects of calcium deficiency on nitrate absorption and on metabolism in tomato. Plant Physiol. 6, 605 (1931). OSERKOWSKY, J. Quantitative relation between chlorophyll and iron in green and chlorotic pear leaves. Plant Physiol. 8, 449 (1933). PAL, R N., and LALORAYA, M..M., Calcium-Sodium interaction in the pod development of the peanut, Arachis hypogaea L. Experientia 23, 382 (1967).
I
f
Effect of Calcium Levels on Chlorophyll Synthesis etc.
449
Role of calcium in growth, metabolic activities and uptake of other ions in plants - A Review. Allahabad Univ. Studies, Botany section, 1-37 (1968). Studies on effects of calcium on growth and metabolic activities of certain crop plants. Ph. D. Thesis, Allahabad University, Allahabad, India (1970). - KAUSHIK, D. D., and LALORAYA, M. M., Effects of calcium on the keto-acids metabolism of peanut, Arachis hypogaea. Z. Pflanzenphysiol. 66, 167 (1972). SMITH, J. H. C., and BENITEZ, A., Chlorophylls: Analysis in plant materials. In: Modern Methods of Plant Analysis, Vol. IV. Eds. PAECH, K., and TRACEY, M. V. Springer Verlag, Germany, 142-192 (1955). T i1cNADA, T., Effect of ribonuclease on salt absorption by excised mung bean roots. Plant Physiol. 31, 251 (1956). VIETS, F. G., Calcium and other polyvalent cations as accelerators of ion accumulation by excised barley roots. Plant Physiol. 19, 466 (1944). WALLACE, T., The diagnosis of mineral deficiencies in plants by visual symptoms. Published by Her Majesty's Stationery Office, London. Third Ed. (1961). Authors' address: Dr. R. N. PAL, Regional Fruit Research Station, Punjab Agricultural University, Abohar, Punjab, and Dr. M. M. LALORAYA, Botany Department, University School of Sciences, Gujarat University, Ahmedabad-9, Gujarat (India).