EFFECT O F G R O W T H RETARDANTS O N G R O W T H A N D ALCALOID F O R M A T I O N IN DATURA M E T E L VAR. FASTUOSA By Mrs. S. GUPTAand C. L. MADAN
Abstract
using a wide range of concentratiovls o f these chemicals from 1000 ppm tvith increases-to 20-40 fold. Of the two chemicals tried B-Nine proved more effective in arresting stem and petiole growth. N o phytotoxicity toas noted with it, whereas high concentrations of CCC like 30000 ppm were toxic'and caused chlorosis even with concentration of 20000 ppm. A decrease of 44% and 40% over control in stem height was observed with 40000 and 20000 ppm B-nine, resulting in a decrease of 40.7 and 26.6% respectively over control in total dry weights of the treated plants. T h e inhibitory effects on height and growth were greater in plants receiving higher doses of B-nine than those receiving lower concentrations. Alkaloid concentration in the leaves increased as a result of these treatments. An increase o f 60% over control in total alkaloids of leaves was found with 20000 ppm B-nine and another increase of 49% was noted with 20000 ppm CCC. lncreases with rest o f the concentrations were insignificant. It appears that generally, higher concentrations o f these chemicals were more conducive to increased alkaloid production but further high doses would become necessary for growth retardation. CCC did not induce significant reductions in height and consequently in the total dry weights of the experimental plants, on the other hand these plants were slightly taller than the controls. Number of leaves and number of nodes per plant were same in treated as well as untreated groups, but node to node distances were reduced in treated plants. Flowering was also delayed as a result of these treatments. Some of these effects suggest that the mode of action of these chemicals is antigibberelfin like in nature. However, the morphological and alkaloidal responses evoked as a result o f treatments with growth retardants are of fundamental and practical value, that may be profitably utilized for large scale ctrltivation of this drug plant for its alkaloids. 111 recent years growth retardants like (2-chloroethyl)~trimethylammonium chloride (CCC)+ N-Dimethyl amino succinamic acid (B995)', phosphon-D and 1 T h e authors hereby acknowledge the help provided in the form of free samples of C C C and B-995 sent by Cyanamid India Ltd., Bombay and U. S. Rubber Company, Nagatl~ckChemical Division, Connecticut, USA.
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Growth retardants CCC and B-nine were applied to yozing plants of Datura metel war. iastuosa in the form of spray at weekly intervals for about 6 weeks,
Gupta and Madan
Planta medica Vol. 28 1975
Amo-1618 have attracted a great deal of attention and have been used for a variety of purposes viz. resistance to environmental stresses, to plant pests and to diseases o r to obtain increased yields in wheat and other cereals, as also in fruits, vegetables and fibre crop. Their use in horticulture is well known [3]. Work of CATHEY in this connection deserves special mention STUART,HUMPHRIES and TOLBERT [3,4, 61. Although a number of reports are available for economic and other crops the information regarding their use on drug plants are very meagre. Growth retardants were first tried on Dattlra spp. by SCIUCHETTI et al. in 1962 [ I , 101. In the present work on ~ a ' t u r mete1 a L. var. fasttrosa which is official in Indian pharmacopoeia and is a potential source for hyoscine, CCC in varying concentrations were used with the object to study whether treatment with any of these chemicals resulted in an increase/decrease in the alkaloidal content and in what manner the growth pattern of treated plants was affected. These studies were started in May 1971 and repeated again in May-June 1972, the plants in both studies were raised from the same seed source. The alkaloidal content was investigated only in leafy portion o f the plant, since leaves are known to contain the nlaxinium alkaloids in this species [ 5 ] .
Materials and Methods Plants used for this s n ~ d ywere raised from seeds of a local strain of D. metel var. fnstrrosa collected in November 1970. Age of seedlings a t the time of transplanting in pots was about 20-25 days. 120 uniform plants each bearing 2 pairs of leaves were selected on 13th May 1971 (Zerotirne) and divided into 12 groups of 10 pla~rtseach. They were labelled as under: 1. CCC treated plants Group C1-treated with 30000 ppm Croup C2-treated with 20000 ppm Group C3-treated with 10 000 ppm Group C4-treated with 5 0 0 0 ppm Group CS-treated with 1000 ppnl Group A-untreated control
CCC CCC CCC CCC CCC
2. B995 treated plants Group B1-treated with 40000 pptn Group B2-treated with 20000 ppm Group B3-treated with 10000 ppni Group B4-treated with 7500 ppm Group BS-treated with 5000 ppm Group A'-untreated control
B995 B995 B995 B995 B995
T h e pots were randonily arranged on a glass house bench and the treatnienrs were then instituted. T h e chemicals used were dissolved in distilled water to prepare the designated strength of the solution. Cycocel containing SOX wlv of rhe active ingredient and B995 (Emulsion) having 5% of the active ingredient were used. N o additional wetting agent was added. A t zero time the aerial parts of the plants were sprayed with a hand sprayer and thoroughly drenched with the aquous solutions containing different concentrations of these chemicals. Care was taken to avoid cross contamination. Specially prepared alknthene shields and cotton plugs inserted a t the point of contact of the main shoot with soil prevented chemical from entering the soil during spraying. An equal dosage of the chemical were given during each spray to the treated plants. The plants received treatments at intervals of 8-10 days. In all 6 treatments were
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Effect of Growth Retardants on Datura
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given. Each time the pots were watered, before the plants were sprayed with the chemicals. Controls were lef&untreated. The 95 days old plants were harvested after a 70 days observation period. The habit of the plants was observed at regular intervals, number of leaves, number of nodes per plant and height measurements were recorded at weekly intervals. T h e total fresh and dry weights of the whole plant of each group were determined a t the time of harvest only. The leafy material was analysed for total alkaloids; For this purpose the leaves were dried in shade, and analysed by the method given in British Pharmacopoeia [2]. Care was taken not to mix more than two plants in a group while sampling unless necessary and thus ensure accuracy in results. 5 gms material was taken each time to analyse and the results reported represent an average of 3 analyses per group (Table I l l ) .
1 . Morphological Responses T h e plants were observed regularIy for any morphological change during the 70 days experimental period following the first application of growth retardants. Statistical analysis of height and dry weight data indicates that of the two chemicals tried B995 was more effective in retarding the shoot elongation of plants. Growth pattern of ~ l a n t streated with this chemical was somewhat different from that of controls. Treated plants were more compact, bushier and some were rather squatter in appearance as compared to the controls (Fig. 1). There was a crowding of leaves near the growing point. New leaves that appeared after the treatment were dark green and thicker and showed a number of variations as regards outline, texture and margins. Some leaves had entire margin, others very much wavy while still others were deeply indentated. Crinkled leaves found in B1 group were small in size as compared to full grown leaves of controls. Crincling of leaves was also observed in other groups like B2 and B3 but to a lesser extent. These changes were noticeable within a week after the first application of the chemical and lasted throughout the experimental period. N o toxicity symptoms were found with any of the 5 concentrations of B995 tried. There was reduction in height in general in plants treated with this chemical. Maximum decrease in height was caused by 40000 and 20000 ppm ppm B995. The heights in these groups were 5 6 and 60% o f the controls. The lower concentrations had little effect in retarding stem elongation. The number of leaves and nodes were practically same in treated as well as untreated plants (TabIe I) but the node to node distance between the treated plants was less than that of the controls. With CCC, there were no appreciable diffei-ences in the habit of treated and untreated plants. Both grew equally tall o r rather the treated plants were slightly
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Results and Discussion
Gupta and Madan
Planta medicn Vol. 28 1975
Figure 1 . Response of Dnturn metel to B Nine treatments Above: C o ~ ~ t r oTreated l; plants: a) 40000 ppm, b) 20000 ppm Note: Retarded eloligation of stems, foliar abnormalities, delayed flowering
taller than the controls (Table I). Higher concentrations of this chemical proved toxic, for instance, there was an acute burning of leaf tips and margins in the plants receiving 30000 ppm CCC within 3-4 days of the first spray, followed by acute chlorosis, resulting in the death of the entire plant. Initially nlild symptoms of chlorosis were found with 20000 ppni CCC also, but these plants recovered later. Plant growth indicated by fresh and dry weights was somewhat reduced by the growth retardants (Table 11). It was inhibited to a greater extent by B995 than by CCC treatment. Plants of group B1 and B2 weighed 59.3 and 73.4% of the controls. SimilarIy the dry weights of other groups like B3, B4 and B5 were also reduced. T h e groups receiving CCC treatment weighed slightly less than the controls, the decrease noticed was insignificant (Table 111).
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Table I Effect of growth retardants CCC & B-Nine on stem height, leaf and node number per/plant
treatment
-
height in cms atzero time
Height in cms after
"No. "No. of one 2 3 4 5 6 7 controlleaves of noweek weeks weeks weeks weeks weeks weeks X des per per plant plant
ppm B 995 40 000 20 000 10 000 7 500 5 000 control A CCCppm 20 000 10 000 5 000 1 000
"
Means average per group of 10 plants
2. Alkaloid production Alkaloid analyses of leaf samples showed variable trends. Group B1 and B2 showed an increase of 17 and 60% in total alkaloids of leaf over the controls. In B3 percentage of total alkaloids in leaf was slightly decreased (Table 111), in B4 it remained the same as in controls while there was a further decrease of 11.4% in group BS. Among CCC treated plants in group C 2 an increase of 49% over the controls was found in total alkaloids of leaf. In C3 there was a decrease of 11.4% while in C4 and C5 an increase of 8.5 and 2.5% over the controls were noted, which is not significant. T h e maximum increases of 60% and 49%.over the controls were found in total alkaloids of leaves with 20000 ppm B995 and 20000 pprn CCC respectively. A critical examination of data shows that generally higher concentrations of these chemicals were effective in increasing the concentration of alkaloids in the leaves to a limited extent only, whereas an increase of 60% was found
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control A
198
Gupta and Madan
Planta medica Vol. 28 1975 T a b l e 11
Fresh and dry weights of Datura metel plants" total weights (in grns.) Fresh Dry
treatment
control (dry weight percentage)
--
1) Control A' pprn B 995 40 000 20 000 10000 7 500 5 000 2) control A 20 000 10000 5 000 1000
" Mean weight per group of
10 plants
T a b l e 111 Co~icentrationof total alkaloids in Daturn metel leaf -
trearnent
-
total alkaloids percentage
control percentage
control ppm B 995 40 000 20 000 10 000 7 500 5 000
pprn CCC 20 000 10 000 5 000 1000
with 20000 pprn B-Nine, with a higher dose i. e., 40000 pprn B-Nine there was an increase of 17%only; similarly with 20000 pprn CCC an increase of 49% was observed but 30000 pprn of the same proved toxic to the plants. Moreover, the increases in total alkaloids were not associated with much decrease in total dry
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pprn CCC
199
weight of the plant. For example maximum reduction in height i. e. 44%and consequently in dry weight 40.7% was observed with 40000 pprn B-Nine, but with 20000 pprn CCC and 20000 pprn B-Nine (the concentrations which resulted in the maximum increases in total alkaloids) reduction in total dry weight was comparatively less i. e. 26 and 21% respectively. T h e significance of this finding implies that these chemicals in specified concentrations could possibly be used with advantage for obtaining increased alkaloidal yield in leaves. B-Nine should be preferred over CCC for spraying on Datura mete1 as this chemical has not proved t o be toxic even in concentrations as high as 40 000 pprn whereas CCC was highly toxic at 30000 pprn and induced chlorosis even a t 20 000 ppm. This study also reveals that for optimum expression of response to the growth retardants the relation to light intensity and temperature should also be considered. For this purpose the spray tests should be conducted during different times of the year. According to CATHEY [3] CCC is much more active in winter, than in summer while reverse is true for phosphon, whereas B-Nine is reported to be active throughout the year. The reason why CCC has not given encouraging results in our experiments may be that this chemical was tried during summer only and not a t any other time of the year. It 'will be worthwhile to try these chemicals during different seasons by varying the dosages in order to obtain maximum response. Field trials should also be performed in order to observe the performance of the plant and the persistance of the effects of these chemicals by sowing seeds harvested from treated plants for next 2-3 generations. Flowering is delayed as a result of these treatments while controls started flowering during the experimental period the treated plants were still in the vegetative stage (Fig. 1). . Lastly as regards mechanism of action of these chemicals our findings are in [lo] i. e. growth retardants behave as antiagreement with those of SCIUCHETTI giberellins as regards alkaloids synthesis and growth behaviour. Gibberellins are known t o lower the concentrations of alkaloids in aerial parts of Datura [7, 8 , 9 ] . The gibberellin treated plants are taller and spindlier with greater internodal elongation, leaves appearing chlorotic, there is increased stem growth and total weight, whereas effects opposite to these have been found with CCC and B-Nine.
Acknowledgements The authors thank Dr. C. K. Atal, Deputy Director Incharge, Regional Research Laboratory, Jammu for his keen interest in the work, Mr. S. Swaroop for taking the photographs and Mr. 0.P. Sharrna drawing the graphs and tables.
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Gupta and Madan
Planta medica Vol. 28 1975
References
Address: Dr.' C . L. Madan, Applied Botany Section, Regional Research' Laboratory ( C . S . I. R.), Canal Road, Jammu-Tawi 180001, India
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[I] BENNET, J. H. and S C I U C H E L. ~ ~A.: I , Journ. Pharm. Sci. 53,lO (1964) [2] British Pharmacopoeia. The Pharmaceutical Press 17, Bloomsbury Square London WC 1 1963 [3] CATHEY,H.M.: Ann. Rev. PI. Physiol. IS, 271 (1964) [4] Cycocel plant growth regulant, Cynamid Technical Information 1966 [5] CUPTA,S. and MADAN,C. L. (In press) Planta rnedica 1973 E. C.: (1968) CCC & Cereals, Rothamsted Experimental Station Report, Har[6] HUMPHRIES, penden, Herts. [ A JAMES,R. P., and S C I U C H E ~L.~A.: I , Journ. Pharm. Sci. S3,9 (1964) [8] MADAN,C. L. and KNDU, B. C.: Planta Medica 10,484 (1962) [9] S C I U C H EL.~ A.: , Joum. Pharm. Sci. S3,l (1964) L. A. and BORN,A. E.: Joum. Pharm. Sci. 5 4 , l (1965) [lo] SCIUCHETTI,
Abstract
using a wide range of concentratiovls o f these chemicals from 1000 ppm tvith increases-to 20-40 fold. Of the two chemicals tried B-Nine proved more effective in arresting stem and petiole growth. N o phytotoxicity toas noted with it, whereas high concentrations of CCC like 30000 ppm were toxic'and caused chlorosis even with concentration of 20000 ppm. A decrease of 44% and 40% over control in stem height was observed with 40000 and 20000 ppm B-nine, resulting in a decrease of 40.7 and 26.6% respectively over control in total dry weights of the treated plants. T h e inhibitory effects on height and growth were greater in plants receiving higher doses of B-nine than those receiving lower concentrations. Alkaloid concentration in the leaves increased as a result of these treatments. An increase o f 60% over control in total alkaloids of leaves was found with 20000 ppm B-nine and another increase of 49% was noted with 20000 ppm CCC. lncreases with rest o f the concentrations were insignificant. It appears that generally, higher concentrations o f these chemicals were more conducive to increased alkaloid production but further high doses would become necessary for growth retardation. CCC did not induce significant reductions in height and consequently in the total dry weights of the experimental plants, on the other hand these plants were slightly taller than the controls. Number of leaves and number of nodes per plant were same in treated as well as untreated groups, but node to node distances were reduced in treated plants. Flowering was also delayed as a result of these treatments. Some of these effects suggest that the mode of action of these chemicals is antigibberelfin like in nature. However, the morphological and alkaloidal responses evoked as a result o f treatments with growth retardants are of fundamental and practical value, that may be profitably utilized for large scale ctrltivation of this drug plant for its alkaloids. 111 recent years growth retardants like (2-chloroethyl)~trimethylammonium chloride (CCC)+ N-Dimethyl amino succinamic acid (B995)', phosphon-D and 1 T h e authors hereby acknowledge the help provided in the form of free samples of C C C and B-995 sent by Cyanamid India Ltd., Bombay and U. S. Rubber Company, Nagatl~ckChemical Division, Connecticut, USA.
Downloaded by: Universite Laval. Copyrighted material.
Growth retardants CCC and B-nine were applied to yozing plants of Datura metel war. iastuosa in the form of spray at weekly intervals for about 6 weeks,
Gupta and Madan
Planta medica Vol. 28 1975
Amo-1618 have attracted a great deal of attention and have been used for a variety of purposes viz. resistance to environmental stresses, to plant pests and to diseases o r to obtain increased yields in wheat and other cereals, as also in fruits, vegetables and fibre crop. Their use in horticulture is well known [3]. Work of CATHEY in this connection deserves special mention STUART,HUMPHRIES and TOLBERT [3,4, 61. Although a number of reports are available for economic and other crops the information regarding their use on drug plants are very meagre. Growth retardants were first tried on Dattlra spp. by SCIUCHETTI et al. in 1962 [ I , 101. In the present work on ~ a ' t u r mete1 a L. var. fasttrosa which is official in Indian pharmacopoeia and is a potential source for hyoscine, CCC in varying concentrations were used with the object to study whether treatment with any of these chemicals resulted in an increase/decrease in the alkaloidal content and in what manner the growth pattern of treated plants was affected. These studies were started in May 1971 and repeated again in May-June 1972, the plants in both studies were raised from the same seed source. The alkaloidal content was investigated only in leafy portion o f the plant, since leaves are known to contain the nlaxinium alkaloids in this species [ 5 ] .
Materials and Methods Plants used for this s n ~ d ywere raised from seeds of a local strain of D. metel var. fnstrrosa collected in November 1970. Age of seedlings a t the time of transplanting in pots was about 20-25 days. 120 uniform plants each bearing 2 pairs of leaves were selected on 13th May 1971 (Zerotirne) and divided into 12 groups of 10 pla~rtseach. They were labelled as under: 1. CCC treated plants Group C1-treated with 30000 ppm Croup C2-treated with 20000 ppm Group C3-treated with 10 000 ppm Group C4-treated with 5 0 0 0 ppm Group CS-treated with 1000 ppnl Group A-untreated control
CCC CCC CCC CCC CCC
2. B995 treated plants Group B1-treated with 40000 pptn Group B2-treated with 20000 ppm Group B3-treated with 10000 ppni Group B4-treated with 7500 ppm Group BS-treated with 5000 ppm Group A'-untreated control
B995 B995 B995 B995 B995
T h e pots were randonily arranged on a glass house bench and the treatnienrs were then instituted. T h e chemicals used were dissolved in distilled water to prepare the designated strength of the solution. Cycocel containing SOX wlv of rhe active ingredient and B995 (Emulsion) having 5% of the active ingredient were used. N o additional wetting agent was added. A t zero time the aerial parts of the plants were sprayed with a hand sprayer and thoroughly drenched with the aquous solutions containing different concentrations of these chemicals. Care was taken to avoid cross contamination. Specially prepared alknthene shields and cotton plugs inserted a t the point of contact of the main shoot with soil prevented chemical from entering the soil during spraying. An equal dosage of the chemical were given during each spray to the treated plants. The plants received treatments at intervals of 8-10 days. In all 6 treatments were
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194
Effect of Growth Retardants on Datura
195
given. Each time the pots were watered, before the plants were sprayed with the chemicals. Controls were lef&untreated. The 95 days old plants were harvested after a 70 days observation period. The habit of the plants was observed at regular intervals, number of leaves, number of nodes per plant and height measurements were recorded at weekly intervals. T h e total fresh and dry weights of the whole plant of each group were determined a t the time of harvest only. The leafy material was analysed for total alkaloids; For this purpose the leaves were dried in shade, and analysed by the method given in British Pharmacopoeia [2]. Care was taken not to mix more than two plants in a group while sampling unless necessary and thus ensure accuracy in results. 5 gms material was taken each time to analyse and the results reported represent an average of 3 analyses per group (Table I l l ) .
1 . Morphological Responses T h e plants were observed regularIy for any morphological change during the 70 days experimental period following the first application of growth retardants. Statistical analysis of height and dry weight data indicates that of the two chemicals tried B995 was more effective in retarding the shoot elongation of plants. Growth pattern of ~ l a n t streated with this chemical was somewhat different from that of controls. Treated plants were more compact, bushier and some were rather squatter in appearance as compared to the controls (Fig. 1). There was a crowding of leaves near the growing point. New leaves that appeared after the treatment were dark green and thicker and showed a number of variations as regards outline, texture and margins. Some leaves had entire margin, others very much wavy while still others were deeply indentated. Crinkled leaves found in B1 group were small in size as compared to full grown leaves of controls. Crincling of leaves was also observed in other groups like B2 and B3 but to a lesser extent. These changes were noticeable within a week after the first application of the chemical and lasted throughout the experimental period. N o toxicity symptoms were found with any of the 5 concentrations of B995 tried. There was reduction in height in general in plants treated with this chemical. Maximum decrease in height was caused by 40000 and 20000 ppm ppm B995. The heights in these groups were 5 6 and 60% o f the controls. The lower concentrations had little effect in retarding stem elongation. The number of leaves and nodes were practically same in treated as well as untreated plants (TabIe I) but the node to node distance between the treated plants was less than that of the controls. With CCC, there were no appreciable diffei-ences in the habit of treated and untreated plants. Both grew equally tall o r rather the treated plants were slightly
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Results and Discussion
Gupta and Madan
Planta medicn Vol. 28 1975
Figure 1 . Response of Dnturn metel to B Nine treatments Above: C o ~ ~ t r oTreated l; plants: a) 40000 ppm, b) 20000 ppm Note: Retarded eloligation of stems, foliar abnormalities, delayed flowering
taller than the controls (Table I). Higher concentrations of this chemical proved toxic, for instance, there was an acute burning of leaf tips and margins in the plants receiving 30000 ppm CCC within 3-4 days of the first spray, followed by acute chlorosis, resulting in the death of the entire plant. Initially nlild symptoms of chlorosis were found with 20000 ppni CCC also, but these plants recovered later. Plant growth indicated by fresh and dry weights was somewhat reduced by the growth retardants (Table 11). It was inhibited to a greater extent by B995 than by CCC treatment. Plants of group B1 and B2 weighed 59.3 and 73.4% of the controls. SimilarIy the dry weights of other groups like B3, B4 and B5 were also reduced. T h e groups receiving CCC treatment weighed slightly less than the controls, the decrease noticed was insignificant (Table 111).
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197
Table I Effect of growth retardants CCC & B-Nine on stem height, leaf and node number per/plant
treatment
-
height in cms atzero time
Height in cms after
"No. "No. of one 2 3 4 5 6 7 controlleaves of noweek weeks weeks weeks weeks weeks weeks X des per per plant plant
ppm B 995 40 000 20 000 10 000 7 500 5 000 control A CCCppm 20 000 10 000 5 000 1 000
"
Means average per group of 10 plants
2. Alkaloid production Alkaloid analyses of leaf samples showed variable trends. Group B1 and B2 showed an increase of 17 and 60% in total alkaloids of leaf over the controls. In B3 percentage of total alkaloids in leaf was slightly decreased (Table 111), in B4 it remained the same as in controls while there was a further decrease of 11.4% in group BS. Among CCC treated plants in group C 2 an increase of 49% over the controls was found in total alkaloids of leaf. In C3 there was a decrease of 11.4% while in C4 and C5 an increase of 8.5 and 2.5% over the controls were noted, which is not significant. T h e maximum increases of 60% and 49%.over the controls were found in total alkaloids of leaves with 20000 ppm B995 and 20000 pprn CCC respectively. A critical examination of data shows that generally higher concentrations of these chemicals were effective in increasing the concentration of alkaloids in the leaves to a limited extent only, whereas an increase of 60% was found
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control A
198
Gupta and Madan
Planta medica Vol. 28 1975 T a b l e 11
Fresh and dry weights of Datura metel plants" total weights (in grns.) Fresh Dry
treatment
control (dry weight percentage)
--
1) Control A' pprn B 995 40 000 20 000 10000 7 500 5 000 2) control A 20 000 10000 5 000 1000
" Mean weight per group of
10 plants
T a b l e 111 Co~icentrationof total alkaloids in Daturn metel leaf -
trearnent
-
total alkaloids percentage
control percentage
control ppm B 995 40 000 20 000 10 000 7 500 5 000
pprn CCC 20 000 10 000 5 000 1000
with 20000 pprn B-Nine, with a higher dose i. e., 40000 pprn B-Nine there was an increase of 17%only; similarly with 20000 pprn CCC an increase of 49% was observed but 30000 pprn of the same proved toxic to the plants. Moreover, the increases in total alkaloids were not associated with much decrease in total dry
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pprn CCC
199
weight of the plant. For example maximum reduction in height i. e. 44%and consequently in dry weight 40.7% was observed with 40000 pprn B-Nine, but with 20000 pprn CCC and 20000 pprn B-Nine (the concentrations which resulted in the maximum increases in total alkaloids) reduction in total dry weight was comparatively less i. e. 26 and 21% respectively. T h e significance of this finding implies that these chemicals in specified concentrations could possibly be used with advantage for obtaining increased alkaloidal yield in leaves. B-Nine should be preferred over CCC for spraying on Datura mete1 as this chemical has not proved t o be toxic even in concentrations as high as 40 000 pprn whereas CCC was highly toxic at 30000 pprn and induced chlorosis even a t 20 000 ppm. This study also reveals that for optimum expression of response to the growth retardants the relation to light intensity and temperature should also be considered. For this purpose the spray tests should be conducted during different times of the year. According to CATHEY [3] CCC is much more active in winter, than in summer while reverse is true for phosphon, whereas B-Nine is reported to be active throughout the year. The reason why CCC has not given encouraging results in our experiments may be that this chemical was tried during summer only and not a t any other time of the year. It 'will be worthwhile to try these chemicals during different seasons by varying the dosages in order to obtain maximum response. Field trials should also be performed in order to observe the performance of the plant and the persistance of the effects of these chemicals by sowing seeds harvested from treated plants for next 2-3 generations. Flowering is delayed as a result of these treatments while controls started flowering during the experimental period the treated plants were still in the vegetative stage (Fig. 1). . Lastly as regards mechanism of action of these chemicals our findings are in [lo] i. e. growth retardants behave as antiagreement with those of SCIUCHETTI giberellins as regards alkaloids synthesis and growth behaviour. Gibberellins are known t o lower the concentrations of alkaloids in aerial parts of Datura [7, 8 , 9 ] . The gibberellin treated plants are taller and spindlier with greater internodal elongation, leaves appearing chlorotic, there is increased stem growth and total weight, whereas effects opposite to these have been found with CCC and B-Nine.
Acknowledgements The authors thank Dr. C. K. Atal, Deputy Director Incharge, Regional Research Laboratory, Jammu for his keen interest in the work, Mr. S. Swaroop for taking the photographs and Mr. 0.P. Sharrna drawing the graphs and tables.
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Effect of Growth Retardants on Datura
200
Gupta and Madan
Planta medica Vol. 28 1975
References
Address: Dr.' C . L. Madan, Applied Botany Section, Regional Research' Laboratory ( C . S . I. R.), Canal Road, Jammu-Tawi 180001, India
Downloaded by: Universite Laval. Copyrighted material.
[I] BENNET, J. H. and S C I U C H E L. ~ ~A.: I , Journ. Pharm. Sci. 53,lO (1964) [2] British Pharmacopoeia. The Pharmaceutical Press 17, Bloomsbury Square London WC 1 1963 [3] CATHEY,H.M.: Ann. Rev. PI. Physiol. IS, 271 (1964) [4] Cycocel plant growth regulant, Cynamid Technical Information 1966 [5] CUPTA,S. and MADAN,C. L. (In press) Planta rnedica 1973 E. C.: (1968) CCC & Cereals, Rothamsted Experimental Station Report, Har[6] HUMPHRIES, penden, Herts. [ A JAMES,R. P., and S C I U C H E ~L.~A.: I , Journ. Pharm. Sci. S3,9 (1964) [8] MADAN,C. L. and KNDU, B. C.: Planta Medica 10,484 (1962) [9] S C I U C H EL.~ A.: , Joum. Pharm. Sci. S3,l (1964) L. A. and BORN,A. E.: Joum. Pharm. Sci. 5 4 , l (1965) [lo] SCIUCHETTI,
