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Effect of cycocel and spacings on the growth and volatile oil of Cymbopogon citratus
Scientia Horticulturae, 8 (1978) 237--242
237
Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
EFFECT OF CYCOCEL AND SPACINGS ON THE GROWTH AND VOLATILE OIL OF CYMBOPOGON CITRATUS
HOSNY M. ELLABBAN
Experimental Station, Faculty of Agriculture, Tanta University, Kafr-EI-Sheikh (A.R. Egypt) (Received 31 August 1977)
ABSTRACT Ellabban, H.M., 1978. Effect of cycocel and spacings on the growth and volatile oil of Cymbopogon eitratus. Scientia Hortic., 8: 237--242.
Cymbopogon citratus, lemongrass, plants were sprayed with cycocel (0, 250, 500, 1000 or 2000 p.p.m.) twice at 2 plant spacings (50 and 75 cm). Significant decreases were noted in the height of the plants and the fresh weight of the above-ground plant parts due to CCC. The percentage of volatile oil in the fresh above-ground parts was increased with a rise in its percentage of citral. The volatile oil content per plant increased with increasing concentration of CCC up to 500 p.p.m, and then tended to decrease. Increasing the distance between the hills had no significant effect on the height of the plants, the percentage of volatile oil or its citral content. However, wider spacing increased the fresh weight of the above-ground parts and the volatile-oil content per plant. Cycocel 500 p.p.m, with 75 cm distance between the hills gave the highest yield of lemongrass oil per plant, and the same concentration with 50 cm distance gave the highest yield of oil per plot. INTRODUCTION
C y m b o p o g o n citratus, Fam. Gramineae, is o n e o f t h e m o s t i m p o r t a n t grasses g r o w n in t h e A.R. E g y p t . Because o f its high citral c o n t e n t , t h e oil possesses a s t r o n g l e m o n o d o u r , w h e n c e t h e n a m e lemongrass. T h e oil o f l e m o n g r a s s is widely used f o r t h e s c e n t i n g o f soaps, d e t e r g e n t s a n d m a n y kinds o f t e c h n i c a l p r o d u c t s . The greatest a m o u n t o f t h e oil, h o w e v e r , is e m p l o y e d f o r t h e isolation o f citral, w h i c h is used in flavors, c o s m e t i c s a n d p e r f u m e s , o r is c o n v e r t e d i n t o i o n o n e s , a g r o u p o f v e r y i m p o r t a n t s y n t h e t i c a r o m a t i c s possessing a s t r o n g a n d lasting p u n g e n t o d o u r . The p l a n t is g r o w n in holes 6 0 - - 9 0 c m a p a r t ( G u e n t h e r , 1 9 5 0 ) . C y c o c e l ( 2 - c h l o r o e t h y l ) - t r i m e t h y l a m m o n i u m chloride (CCC) is well k n o w n as a g r o w t h r e t a r d a n t , s h o r t e n i n g t h e plants, a n d enabling t h e m t o w i t h s t a n d higher doses o f N fertilizer, w i t h o u t lodging, resulting in h i g h e r yield ( H u m p h r i e s et al., 1 9 6 5 f o r w h e a t ; A b i d i a n d Malik, 1 9 7 3 f o r rice). I t has b e e n r e p o r t e d t o be effective in accelerating a n d increasing t h e y i e l d o f
238 several crops (Halevy and Wittwer, 1965 for snapdragon; Monselise et al., 1966 for lemon; Adedipe et al., 1968 for pea; Okoloko and Lewis, 1968 for Coleus blumei; van Bragt, 1969 for tomato; Heide, 1969 for begonia; Wusche, 1969 for snapdragon). Little work has been done on the effect of CCC on medicinal and aromatic plants. Andries and Lamba (1967) found in H y o s c y a m u s albus that cycocel reduced the vegetative growth with a rise in alkaloid content. Abou-Zeid and Sherbeeny (1971) concluded that application of CCC to Matricaria c h a m o milla shortened plant height and spreading-area, b u t increased flower yield with a rise in volatile oil percent and its chamazulene content. H o o k et a l . (1973) concluded that Mentha piperita plants treated with cycocel showed reduction in hydrocarbons and menthol, b u t increases in methone and methyl acetate. The distance between plants is an important factor which has a striking influence on the yield and volatile oil content of aromatic plants. Many workers mentioned that while the plant yield was greater with wider spacing, the yield per unit area was less. They found optimal distances for each individual plant. These were determined b y Milcev et al. (1963) for lavender, Plytnikova (1964) for coriander, Agena (1966) and Bukhbinder (1973) for geranium, Berbec (1968) for Valeriana officinalis vat. tenuifolia, Peneva (1969) for pyrethrum, and Oda (1972) for sage. Plant spacing had n o significant effect on the percentage of oil in the leaves (Berbec, 1968 for valeriana; Styk, 1969 for fennel; Ellabban et al., 1972 for anise; Oda, 1972 for sage). On the other hand, wide plant spacing gave a higher percentage of volatile oil (Milcev et al., 1963 for lavender; Agena, 1966 for geranium; Oda, 1972 for rosemary). Youngken (1948) reported that oil of C y m b o p o g o n citratus contains 53--80% citral. Guenther (1950) reported that C y m b o p o g o n citratus grass contains 0.23 0.58% of oil, while the oil contains 70--82% citral. The present study was c o n d u c t e d to examine the effect of cycocel and spacing on the growth and oil content o f C y m b o p o g o n citratus. MATERIALS AND METHODS Clumps of C y m b o p o g o n citratus were divided into uniform slips and planted on 3 April 1974 at 50 or 75 cm in rows 50 cm apart. The area of each plot was 2 × 3 m; hence there were 24 or 16 plants per plot. On 30 April the plants were fertilized with 100 kg ammonium sulphate (20% N), 100 kg c ~ c i u m superphosphate (16% P2Os) and 50 kg potassium sulphate (48% K20) per 4200 m 2 (= 1 feddan). An equal a m o u n t was added 4 weeks later. The various concentrations of cycocel used (0, 250, 500, 1000 and 2000 p.p.m, in water solution) were sprayed on 15 May and 5 June 1974. The 2 spacings (50 and 75 cm) were combined with spraying with each concentration. The 10 treatments were repeated 4 times in a randomized complete block design. Irrigation was done regularly. On 28 August 1974 the plant
239
height was measured. The above-ground parts (grass) were cut 10 cm above ground and weighed. Volatile oil was determined by the m e t h o d recommended in the Egyptian Pharmacopoea (1963). The citral c o n t e n t of the oil was determined by the m e t h o d of Guenther (1948). RESULTS AND DISCUSSION Table 1 shows t h a t all the plants treated with cycocel were shorter than the controls. The concentrations 500, 1000 and 2000 p.p.m, o f CCC gave significantly shorter plants than 250 p.p.m, or the control. CCC at 1000 and 2000 p.p.m, gave an almost equal effect and resulted in the shortest plants among all treatments, with both spacings. Increasing the distance between hills from 50 to 75 cm tended to decrease the height of the plants, but n o t significantly. The fresh weight of the above-ground parts significantly decreased due to spraying the plants with CCC compared to the control, 2000 p.p.m, giving the lowest weights among all the treatments. There were significant differences in the fre.~h weights of Cymbopogon citratus above-ground parts per plant in favour of wider spacing between hills. This may be attributed to the o p p o r t u n i t y of wider-spaced plants to increase the synthesis of metabolites, resulting in growth of more stems and roots. The % volatile oil of the fresh above-ground parts siginificantly increased when using 500, 1000 and 2000 p.p.m, of cycocel in comparison with 250 p.p.m, or the control. Increasing the spacing between the hills from 50 to 75 cm had no significant effect on the % of the oil. There was an increase in the percentage of citral in the volatile oil due to spraying the plants with CCC. This may demonstrate the fact t h a t cycocel has an activating-effect on the citral synthesis as well as on volatile oil formation. Cleland (1965) concluded t h a t there is more than one mode of action of CCC, and t h a t its action may differ according to the species, the tissue and the response studied. Under the conditions of this experiment, increasing the distance between the plants had no effect on the % of citral in the volatile oil. The volatile oil c o n t e n t per plantincreased due to spraying the plants with CCC up to 500 p.p.m, and then tended to decrease. The wider spacings gave significantly higher yield of oil per plant than the closer ones. With 75 cm between hills, cycocel at 500 p.p.m, gave the highest yield of off per plant. Considering the yield of oil per plot, the results were different from those per plant. The yield of oil of lemongrass per plot increased with decreasing the distance between hills. This may be due to the inability of the increase due to wider spacing to counterbalance the increases in the number of plants per plot in the close spacing. The t r e a t m e n t at 50 cm of 500 p.p.m. CCC gave the highest yield per plot among all treatments.
Height of plants (cm)
117.3 111.8 98.4 86.7 86.2 115.5 108,1 99.7 86'9 84.5 8.5
Treatments (spacing in cm and p.p.m, of CCC)
0 250 500 1000 2000 0 250 500 1000 2000
1. 50 + 2. 50 + 3. 5 0 + 4. 50 + 5.50 + 6.75 + 7.75 + 8.75 + 9.75 + 10. 75 +
L.S.D. at 0.05
17.2
316.1 296.8 293.5 277.2 265.0 337.8 321.4 311.9 295.4 279.5
/plant (g)
Weight of fresh aboveground parts
0.047
0.337 0.373 0.410 0.392 0.411 0.335 0.381 0.415 0.416 0.408
% of volatile oil in fresh above-ground parts 74.50 74.80 75.90 75.55 75.80 74.30 75.90 75.85 75.90 75.75
Citral in volatile oil(%)
Effect of cycocel and spacing on t h e growth and volatile oil of Cymbopogon citratus
TABLE 1
0.089
1.066 1.108 1.201 1.084 1.086 1.133 1.226 1.295 1.228 1.139
Volatile oil c o n t e n t per plant (ml) 25.584 26.592 28.824 26.016 26.064 18.128 19.616 20.720 19.648 18.224
Volatile oil per plot (ml)
0
b~
241
Several of m y results confirm those of other workers with other plants, as was discussed in the introduction. ACKNOWLEDGEMENT
The a u t h o r is greatly indebted to Dr. D.B. Williams, Professor and Head, Department of Ornamental Horticulture and Landscape Design, University of Tennessee, Knoxville, U.S.A. for fruitful discussions and c o m m e n t during the writing of this paper. REFERENCES Abidi, Z.H. and Malik, A.J., 1973. Effect of cycocel on plant height and seed index of rice. Trop. Abstr., 28: 22. Abou-Zeid, E.N. and Sherbeeny, S.S., 1971. Effect of cycocel on flower production and volatile of Matricaria chamomilla L. Z. Pflanzenphysiol., 65: 35--58. Adedipe, N.O., Ormord, D.P. and Maurer, A.R., 1968. Response of pea plants to soil and foliar applications of cycocel (2-chloroethyltrimethylammonium chloride). Can. J. Plant Sci., 48: 323--325. Agena, E.A., 1966. Effect of some cultural treatments on the growth and oil yield of geranium plants. M.Sc. Thesis, Agric. Fac., Ain Shams University. Andries, M.C. and Lamba, S.S., 1967. Effects of (2-chloroethyl) trimethyl a m m o n i u m chloride (CCC) on Hyoscyamus albus plants. Phyton, 24: 1--6. Berbec, S., 1968. The effect of spacing and hoeing on the quality and quantity of harvested Valeriana. Hortic. Abstr., 1970, 40: 9100. Bragt, J. van, 1969. The effect of CCC on growth and gibberellin content of tomato plants. Neth. J. Agric. Sci., 17: 183--188. Bukhbinder, A.A., 1973. The effect of planting density on the development in the Kolkhida lowland. Hortic. Abstr., 1974, 44: 3438. Cleland, R., 1965. Evidence on the site of action of growth retardants. Plant Cell Physiol., 6: 7--15. Egyptian Pharmacopoeia, 1963. Ellabban, H.M., Mahran, G.H. and E1-Hossary, G.A., 1972. Effect of planting distances and number of plants per drill on the growth and yield of Pimpinella anisum Faro. Umbelliferae. Bull. Fac. Pharm., Cairo Univ., 11: 371--381. Guenther, E., 1948. The Essential Oils. Vol. 1, Van Nostrand, New York, pp. 285--291. Guenther, E., 1950. The Essential Oils. Vol. 4, Van Nostrand, New York, pp. 18--64. Halevy, A.H. and Wittwer, S.H., 1965.-Growth promoting in the snapdragon by CCC, a growth retardant. Naturwissenschaften, 52: 310. Heide, O.M., 1969. Interaction of growth retardants and temperature in growth, flowering, regeneration, and auxin activity of Begonia × cheimantha Everett. Physiol. Plant., 22: 1001--1012. Hook, I.L.I., O'Connor, C.S. and Timoney, R.F., 1973. Some effects of chlorocholine chloride on Mentha piperita. Planta Med., 2 4 : 2 4 9 259. Humphries, E.C., Welbank, P.J. and Wilts, K.J., 1965. Effect of CCC on growth and yield of spring wheat in the field. Ann. Appl. Biol., 56: 351--361. Milcev, M.P., Atanassov, Z.D. and Cingova, B.G., 1963. On the antierosion role of Lavender. Hortic. Abstr., 34: 3492. Monsel~se, S.P., Goren, R. and Halevy, A.H., 1966. Effects of B-nine, cycocel and ber/zothiazole oxyacetate on flower bud induction of lemon trees. Proc. Am. Soc. Hortic. Sci., 89: 195--200.
242
Oda, H.E.S., 1972. Effect of nitrogen fertilization and plant spacing on growth and essential oil production of sage and rosemary. M.Sc. Thesis, Agric. Fac., Cairo University. Okoloko, G.E. and Lewis, L.N., 1968. Enhancement of lateral bud growth in Coleus blumei Benth. by (2-chloroethyl)-trimethylammoniumchloride (CCC). Plant Cell Physiol., 9: 259--266. Peneva, P., 1969. The influence of spacing on the growth and yield of Dalmation pyrethrum (Pyrethrum einerarifolium), Hortic. Abstr., 40: 2012, Plytnikova, T.G., 1964. Increasing the coefficient of multiplication in coriander seed production. Hortic. Abstr. 35: 4120. Styk, B., 1969. The effect of spacing, number of plants and size of transplants on the yield of fennel. Hortic. Abstr., 42: 1958. Wusche, U., 1969. Growth retarding and stimulating effects of CCC on Antirrhinum majus L. Planta (Berlin), 85: 108--110. Youngken, H,W., 1948. Text book of Pharmacognosy. 6th edn. Blakiston, Philadelphia, Toronto.
237
Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
EFFECT OF CYCOCEL AND SPACINGS ON THE GROWTH AND VOLATILE OIL OF CYMBOPOGON CITRATUS
HOSNY M. ELLABBAN
Experimental Station, Faculty of Agriculture, Tanta University, Kafr-EI-Sheikh (A.R. Egypt) (Received 31 August 1977)
ABSTRACT Ellabban, H.M., 1978. Effect of cycocel and spacings on the growth and volatile oil of Cymbopogon eitratus. Scientia Hortic., 8: 237--242.
Cymbopogon citratus, lemongrass, plants were sprayed with cycocel (0, 250, 500, 1000 or 2000 p.p.m.) twice at 2 plant spacings (50 and 75 cm). Significant decreases were noted in the height of the plants and the fresh weight of the above-ground plant parts due to CCC. The percentage of volatile oil in the fresh above-ground parts was increased with a rise in its percentage of citral. The volatile oil content per plant increased with increasing concentration of CCC up to 500 p.p.m, and then tended to decrease. Increasing the distance between the hills had no significant effect on the height of the plants, the percentage of volatile oil or its citral content. However, wider spacing increased the fresh weight of the above-ground parts and the volatile-oil content per plant. Cycocel 500 p.p.m, with 75 cm distance between the hills gave the highest yield of lemongrass oil per plant, and the same concentration with 50 cm distance gave the highest yield of oil per plot. INTRODUCTION
C y m b o p o g o n citratus, Fam. Gramineae, is o n e o f t h e m o s t i m p o r t a n t grasses g r o w n in t h e A.R. E g y p t . Because o f its high citral c o n t e n t , t h e oil possesses a s t r o n g l e m o n o d o u r , w h e n c e t h e n a m e lemongrass. T h e oil o f l e m o n g r a s s is widely used f o r t h e s c e n t i n g o f soaps, d e t e r g e n t s a n d m a n y kinds o f t e c h n i c a l p r o d u c t s . The greatest a m o u n t o f t h e oil, h o w e v e r , is e m p l o y e d f o r t h e isolation o f citral, w h i c h is used in flavors, c o s m e t i c s a n d p e r f u m e s , o r is c o n v e r t e d i n t o i o n o n e s , a g r o u p o f v e r y i m p o r t a n t s y n t h e t i c a r o m a t i c s possessing a s t r o n g a n d lasting p u n g e n t o d o u r . The p l a n t is g r o w n in holes 6 0 - - 9 0 c m a p a r t ( G u e n t h e r , 1 9 5 0 ) . C y c o c e l ( 2 - c h l o r o e t h y l ) - t r i m e t h y l a m m o n i u m chloride (CCC) is well k n o w n as a g r o w t h r e t a r d a n t , s h o r t e n i n g t h e plants, a n d enabling t h e m t o w i t h s t a n d higher doses o f N fertilizer, w i t h o u t lodging, resulting in h i g h e r yield ( H u m p h r i e s et al., 1 9 6 5 f o r w h e a t ; A b i d i a n d Malik, 1 9 7 3 f o r rice). I t has b e e n r e p o r t e d t o be effective in accelerating a n d increasing t h e y i e l d o f
238 several crops (Halevy and Wittwer, 1965 for snapdragon; Monselise et al., 1966 for lemon; Adedipe et al., 1968 for pea; Okoloko and Lewis, 1968 for Coleus blumei; van Bragt, 1969 for tomato; Heide, 1969 for begonia; Wusche, 1969 for snapdragon). Little work has been done on the effect of CCC on medicinal and aromatic plants. Andries and Lamba (1967) found in H y o s c y a m u s albus that cycocel reduced the vegetative growth with a rise in alkaloid content. Abou-Zeid and Sherbeeny (1971) concluded that application of CCC to Matricaria c h a m o milla shortened plant height and spreading-area, b u t increased flower yield with a rise in volatile oil percent and its chamazulene content. H o o k et a l . (1973) concluded that Mentha piperita plants treated with cycocel showed reduction in hydrocarbons and menthol, b u t increases in methone and methyl acetate. The distance between plants is an important factor which has a striking influence on the yield and volatile oil content of aromatic plants. Many workers mentioned that while the plant yield was greater with wider spacing, the yield per unit area was less. They found optimal distances for each individual plant. These were determined b y Milcev et al. (1963) for lavender, Plytnikova (1964) for coriander, Agena (1966) and Bukhbinder (1973) for geranium, Berbec (1968) for Valeriana officinalis vat. tenuifolia, Peneva (1969) for pyrethrum, and Oda (1972) for sage. Plant spacing had n o significant effect on the percentage of oil in the leaves (Berbec, 1968 for valeriana; Styk, 1969 for fennel; Ellabban et al., 1972 for anise; Oda, 1972 for sage). On the other hand, wide plant spacing gave a higher percentage of volatile oil (Milcev et al., 1963 for lavender; Agena, 1966 for geranium; Oda, 1972 for rosemary). Youngken (1948) reported that oil of C y m b o p o g o n citratus contains 53--80% citral. Guenther (1950) reported that C y m b o p o g o n citratus grass contains 0.23 0.58% of oil, while the oil contains 70--82% citral. The present study was c o n d u c t e d to examine the effect of cycocel and spacing on the growth and oil content o f C y m b o p o g o n citratus. MATERIALS AND METHODS Clumps of C y m b o p o g o n citratus were divided into uniform slips and planted on 3 April 1974 at 50 or 75 cm in rows 50 cm apart. The area of each plot was 2 × 3 m; hence there were 24 or 16 plants per plot. On 30 April the plants were fertilized with 100 kg ammonium sulphate (20% N), 100 kg c ~ c i u m superphosphate (16% P2Os) and 50 kg potassium sulphate (48% K20) per 4200 m 2 (= 1 feddan). An equal a m o u n t was added 4 weeks later. The various concentrations of cycocel used (0, 250, 500, 1000 and 2000 p.p.m, in water solution) were sprayed on 15 May and 5 June 1974. The 2 spacings (50 and 75 cm) were combined with spraying with each concentration. The 10 treatments were repeated 4 times in a randomized complete block design. Irrigation was done regularly. On 28 August 1974 the plant
239
height was measured. The above-ground parts (grass) were cut 10 cm above ground and weighed. Volatile oil was determined by the m e t h o d recommended in the Egyptian Pharmacopoea (1963). The citral c o n t e n t of the oil was determined by the m e t h o d of Guenther (1948). RESULTS AND DISCUSSION Table 1 shows t h a t all the plants treated with cycocel were shorter than the controls. The concentrations 500, 1000 and 2000 p.p.m, o f CCC gave significantly shorter plants than 250 p.p.m, or the control. CCC at 1000 and 2000 p.p.m, gave an almost equal effect and resulted in the shortest plants among all treatments, with both spacings. Increasing the distance between hills from 50 to 75 cm tended to decrease the height of the plants, but n o t significantly. The fresh weight of the above-ground parts significantly decreased due to spraying the plants with CCC compared to the control, 2000 p.p.m, giving the lowest weights among all the treatments. There were significant differences in the fre.~h weights of Cymbopogon citratus above-ground parts per plant in favour of wider spacing between hills. This may be attributed to the o p p o r t u n i t y of wider-spaced plants to increase the synthesis of metabolites, resulting in growth of more stems and roots. The % volatile oil of the fresh above-ground parts siginificantly increased when using 500, 1000 and 2000 p.p.m, of cycocel in comparison with 250 p.p.m, or the control. Increasing the spacing between the hills from 50 to 75 cm had no significant effect on the % of the oil. There was an increase in the percentage of citral in the volatile oil due to spraying the plants with CCC. This may demonstrate the fact t h a t cycocel has an activating-effect on the citral synthesis as well as on volatile oil formation. Cleland (1965) concluded t h a t there is more than one mode of action of CCC, and t h a t its action may differ according to the species, the tissue and the response studied. Under the conditions of this experiment, increasing the distance between the plants had no effect on the % of citral in the volatile oil. The volatile oil c o n t e n t per plantincreased due to spraying the plants with CCC up to 500 p.p.m, and then tended to decrease. The wider spacings gave significantly higher yield of oil per plant than the closer ones. With 75 cm between hills, cycocel at 500 p.p.m, gave the highest yield of off per plant. Considering the yield of oil per plot, the results were different from those per plant. The yield of oil of lemongrass per plot increased with decreasing the distance between hills. This may be due to the inability of the increase due to wider spacing to counterbalance the increases in the number of plants per plot in the close spacing. The t r e a t m e n t at 50 cm of 500 p.p.m. CCC gave the highest yield per plot among all treatments.
Height of plants (cm)
117.3 111.8 98.4 86.7 86.2 115.5 108,1 99.7 86'9 84.5 8.5
Treatments (spacing in cm and p.p.m, of CCC)
0 250 500 1000 2000 0 250 500 1000 2000
1. 50 + 2. 50 + 3. 5 0 + 4. 50 + 5.50 + 6.75 + 7.75 + 8.75 + 9.75 + 10. 75 +
L.S.D. at 0.05
17.2
316.1 296.8 293.5 277.2 265.0 337.8 321.4 311.9 295.4 279.5
/plant (g)
Weight of fresh aboveground parts
0.047
0.337 0.373 0.410 0.392 0.411 0.335 0.381 0.415 0.416 0.408
% of volatile oil in fresh above-ground parts 74.50 74.80 75.90 75.55 75.80 74.30 75.90 75.85 75.90 75.75
Citral in volatile oil(%)
Effect of cycocel and spacing on t h e growth and volatile oil of Cymbopogon citratus
TABLE 1
0.089
1.066 1.108 1.201 1.084 1.086 1.133 1.226 1.295 1.228 1.139
Volatile oil c o n t e n t per plant (ml) 25.584 26.592 28.824 26.016 26.064 18.128 19.616 20.720 19.648 18.224
Volatile oil per plot (ml)
0
b~
241
Several of m y results confirm those of other workers with other plants, as was discussed in the introduction. ACKNOWLEDGEMENT
The a u t h o r is greatly indebted to Dr. D.B. Williams, Professor and Head, Department of Ornamental Horticulture and Landscape Design, University of Tennessee, Knoxville, U.S.A. for fruitful discussions and c o m m e n t during the writing of this paper. REFERENCES Abidi, Z.H. and Malik, A.J., 1973. Effect of cycocel on plant height and seed index of rice. Trop. Abstr., 28: 22. Abou-Zeid, E.N. and Sherbeeny, S.S., 1971. Effect of cycocel on flower production and volatile of Matricaria chamomilla L. Z. Pflanzenphysiol., 65: 35--58. Adedipe, N.O., Ormord, D.P. and Maurer, A.R., 1968. Response of pea plants to soil and foliar applications of cycocel (2-chloroethyltrimethylammonium chloride). Can. J. Plant Sci., 48: 323--325. Agena, E.A., 1966. Effect of some cultural treatments on the growth and oil yield of geranium plants. M.Sc. Thesis, Agric. Fac., Ain Shams University. Andries, M.C. and Lamba, S.S., 1967. Effects of (2-chloroethyl) trimethyl a m m o n i u m chloride (CCC) on Hyoscyamus albus plants. Phyton, 24: 1--6. Berbec, S., 1968. The effect of spacing and hoeing on the quality and quantity of harvested Valeriana. Hortic. Abstr., 1970, 40: 9100. Bragt, J. van, 1969. The effect of CCC on growth and gibberellin content of tomato plants. Neth. J. Agric. Sci., 17: 183--188. Bukhbinder, A.A., 1973. The effect of planting density on the development in the Kolkhida lowland. Hortic. Abstr., 1974, 44: 3438. Cleland, R., 1965. Evidence on the site of action of growth retardants. Plant Cell Physiol., 6: 7--15. Egyptian Pharmacopoeia, 1963. Ellabban, H.M., Mahran, G.H. and E1-Hossary, G.A., 1972. Effect of planting distances and number of plants per drill on the growth and yield of Pimpinella anisum Faro. Umbelliferae. Bull. Fac. Pharm., Cairo Univ., 11: 371--381. Guenther, E., 1948. The Essential Oils. Vol. 1, Van Nostrand, New York, pp. 285--291. Guenther, E., 1950. The Essential Oils. Vol. 4, Van Nostrand, New York, pp. 18--64. Halevy, A.H. and Wittwer, S.H., 1965.-Growth promoting in the snapdragon by CCC, a growth retardant. Naturwissenschaften, 52: 310. Heide, O.M., 1969. Interaction of growth retardants and temperature in growth, flowering, regeneration, and auxin activity of Begonia × cheimantha Everett. Physiol. Plant., 22: 1001--1012. Hook, I.L.I., O'Connor, C.S. and Timoney, R.F., 1973. Some effects of chlorocholine chloride on Mentha piperita. Planta Med., 2 4 : 2 4 9 259. Humphries, E.C., Welbank, P.J. and Wilts, K.J., 1965. Effect of CCC on growth and yield of spring wheat in the field. Ann. Appl. Biol., 56: 351--361. Milcev, M.P., Atanassov, Z.D. and Cingova, B.G., 1963. On the antierosion role of Lavender. Hortic. Abstr., 34: 3492. Monsel~se, S.P., Goren, R. and Halevy, A.H., 1966. Effects of B-nine, cycocel and ber/zothiazole oxyacetate on flower bud induction of lemon trees. Proc. Am. Soc. Hortic. Sci., 89: 195--200.
242
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