CAPITULUM INITIATION OF GARLAND CHRYSANTHEMUM VEGETABLE ENCHANCED BY PLANT GROWTH REGULATOR

 

PENINGKATAN INISIASI KAPITULUM GARLAND CHRYSANTHEMUM

DENGAN ZAT PENGATUR TUMBUH

 

Yulian

Program Studi Agronomi Fakultas Pertanian  Universitas Bengkulu

 

ABSTRACT

Effects of plant growth regulators on flowering of garland chrysanthemum (Chrysanthemum coronarium L.) were investigated. In experiment 1, seeds of six cvs. Tatsunami, Hakata Kairyou chuuba, Kabuhari chuuba, Kabuhari, Otafuku and Koji Ooba were hastened to promote the germination in growth chamber (NK System Biotron) with 23°C and 14 hr.  Germinated seeds were sown in 15 cm plastic pot on May 2 (longday) and September 10, 1994 (shortday) under natural condition in plastic house.  After the seedlings passed their juvenile phase, they were divided into 4 groups each consisting of 8 plants.  Plants were sprayed 4 times by 10 mL of 50 and 100 ppm GA and 1000 ppm SADH solution at 1-week intervals.  The budding plant was observed. Flowering of garland chrysanthemum had been strongly affected with plant growth regulators treatment.  The budding occurred in all treatmen under long day season.  But, budding of GA₃ treated plants occurred earlier than that of control plants.  In contrast, budding of SADH treated plants occurred the latest one.  In addition. There was no different on budding between 50 and 100 ppm GA treated plants. In experiment 2, As for plant material, cv. Hakata kairyou chuuba which has a good response to GA₃ and SADH treatment on flowering was used. The seedling maintenance were the same as experiment 1.  When cotyledons expanded, seedlings were transferred in phytotron. After the leaf number seven or eight opened, the seedlings were divided into 3 plots, each consisting of 60 or 90 plants per plot.  A 10 mL per plant of 100 ppm GA or 1000 ppm SADH solution were sprayed at 1-week intervals for 3 to 4 times. The shoot tips were observed under a stereoscopic microscope, the floral stages were recorded. The experiment was stopped when the capitulum of all plots formed. As aresults, the capitulum initiation was promoted by GA₃ and it was delayed by SADH  treatment. The capitulum developments were promoted  by exposing in longdays.

 

 

ABSTRAK

Pengaruh GA₃ dan SADH  terhadap proses pembungaan garland chrysanthemum (Chrysanthemum coronarium L.) telah dipelajari secara intensif. Pada percobaan 1, digunakan 6 kultivar yaitu Tatsunami, Hakata Kairyou chuuba, Kabuhari chuuba, Kabuhari, Otafuku and Koji Ooba. Benih dikecambahkan di dalam growth chamber (NK System Biotron)  pada suhu 23°C dan cahaya  14 jam.  Pada tanggal 2 Mei dan 10 September 1994, benih yang telah berkecambah disemaikan pada pot plastik yang berdiameter 15 cm dan dipelihara di rumah plastik. Pada saat tanaman masih pada fase juvenil, dikelompokkan menjadi 4 grup masingt-masing 8 tanaman. Tanaman disemprot sebanyak 4 kali pada interval 1 minggu dengan  larutan GA₃ 10 mL,  50 dan 100 ppm, serta SADH 1000 ppm.  Waktu muncul bunga diamati sejak pertama sampai akhir pembungaan. Hasilnya diketahui bahwa pembungaan garland chrysanthemum sangat tegas dipengaruhi oleh perlakuan zat pengatur tumbuh. Bunga muncul pada semua perlakuan pada saat hari panjang. Tetapi, bunga tanaman yang menerima perlakuan GA3 muncul lebih dahulu dari pada tanaman kontrol. Namun demikian, tidak ada perbedaan waktu muncul bunga antara tanaman yang mendapat perlakuan 50 dan 100 ppm GA3. Sebaliknya, bunga tanaman yang menerina perlakuan SADH muncul sangat terlambat. Pada percobaan 2, hanya kultivar Hakata kairyou chuuba yang digunakan karena responya yang paling baik terhadap perlakuan GA₃ dan SADH pada percobaan 1. Proses perkecambahan pada percobaan ini sama dengan percobaan 1. Setelah disemai dan kotiledon muncul, tanaman di pindahkan kedalam ruang phytotron. Tanaman dikelompokkan menjadi 3 grup dan setelah mempunyai 8 daun disemprot dengan 10 mL per tanaman larutan GA₃ 100 ppm dan 1000 ppm SADH setiap minggu sebanyak 4 kali. Kondisi morfologi floral stage pucuk diamati menggunakan stereoscopic microscope. Percobaan distop pada saat semua tanaman membentuk bunga. Hasilnya ditemukan bahwa inisiasi organ-organ bunga distimulasi oleh perlakuan GA₃ dan sebaliknya dihambat oleh SADH. Sedangkan proses perkembangan organ-organ tersebut dipacu dengan adanya kondisi  hari panjang.

INTRODUCTION

 

In the previous experiment, althhough long-day and cool temperature condition are necessary to induce early flower bud initiation garland chry-santhemum cv. Hakata kairyou chuuba, however, it was found that the capitulum initiation and development were delayed with longday and high temperature.  Presently, study on flowering of the culltivars had been more intensive.  In many case, it is known that GA₃ treatment promote flowering. GA₃ is used to promote rapid growth, tall plants, and presently is utilized to replace the effects of longday to induce early capitulum initiation.  But, anti-GA₃ (SADH) in contrast inhibit flowering. 

          As to the flowering of garland chrysanthe-mum, (Kobayashi and Matsuda 1975; Suzuki, 1977; Mochizuki and Hiraoka, 1978; Takahashi et al., 1981; Iwami et al., 1983; Javier, 1990) repor-ted that the capitulum initiation was pro-moted by longday, but Javier (1990) reported that flowering was promoted by shortday in Taiwan.

          In the previous experiment, it was found that there was a cultivar difference on  flowering response in spring and autumn.  The capitulums became visible earlier in spring than autumn season. Average air temperature in spring was lower than in autumn season.  Also the daylength in spring was slightly longer than in autumn season.  It might be due to the difference of environmental condition in field.  When the daylength treatment had been conducted in both under spring and autumn seasons, the capitulum became visible earlier under longday in spring season for all cultivars examined, but only the capitulum of early cultivar became visible under longday in summer season.   Therefore, since the longday in spring season was thought to be inductive condition than that under shorter daylengths with temperature in summer season.  When the time of capitulum initiation was compared at the temperatures from 15° to 30°C under 16 hr daylength, it was observed that the lower growing temperature, the earlier the capitulum was.  Since the capitulum were initiated only under longday, therefore the longday condition was considere as a main factor to induce capitulum initiation of garland chrysanthe-mum.  The temperature itself was thought to be an additional factor, because the capitulum was initiated eaarlier and at fewer nodes as the growing temperature declined.

         

The involvement of plant growth regulators in flowering has been reported in some crops, such as Chrysanthemum, broccoli and cauliflower (Fujime, 1978).  Tsukamoto (1959) reported that in the case of use of light in culturing chrysan-themum, it is well recognized that the efficiency of illumination on the retardation of flowering decreases when the intensity of light is not suffi-cient.  When the grower can replace the light with auxin application for flower retardation, it is convenient for light culture in the field where electric facilities are not available. Fujime (1988) dealt with the study on the effects of some chemical disbudding and the method of treatmen.  He introduced the way for labor saving methods to replace the job of pruning, pinching and disbud-ding that is still depend largely on human labor in growing chrysanthemum for flower ornamental.  In contrast, it is necessary to accelerate lateral shoot branching that is commonly found some-times to increase the yield to broccoli and cauli-flower.  There is only one report about the promotion of the capitulum initiation using GA₃ application on garland chrysanthemum (Hiraoka and Mochizuki, 1978), but there was no report about anti-GA₃ to inhibit flowering.

          For garland chrysanthemum, although the GA₃ application accelerated only the internode elongation, but no effect on flower bud differenti-ation (Hiraoka and Mochizuki (1978).  It is necessary to re-examination on the role of GA₃ and anti-GA₃ on flowering process of garland chrysanthemum, using more cultivars grown under long or shortday conditions. In this exxperiment, the effect of those GA₃ and SADH, and growing temperature on capitulum initiation and develop-ment were also investigated.

 

MATERIALS AND METHODS

 

Experiment 1

 

Seeds of six cvs. Tatsunami, Hakata kairyou chuuba, Kabuhari chuuba, Kabuhari, Otafuku and Koji Ooba were hastened to promote germination in growth chamber (NK Sytem Biotron) with 23°C and 14 hr.  Germinated seeds were sown in 15 cm plastic pot on May 2 (longday season) and September 10, 1994 (shortday season) under natural condition in plastichouse.  After the seed-lings passed their juvenile phase, they were divided into 4 groups each consisting of 8 plants.  A 10 mL of 50 and 100 ppm GA₃ and 1000 ppm SADH solution were sprayed 4 times at 1 week intervals.  The date of budding was measured.

 

Experiment 2

          As for plant material, garland chrysanthe-mum cultivar Hakata kairyou chuuba has a good response to GA₃ and SADH treatment on flowering were used.

          The seeds were hastened to promote germination in growth chamber (NK System Biotron) provided with 23°C and 14 hr daylength on January and May.  The germinated seeds were sown into seeding boxes (28 cm x 52 cm) on January 25 (shortday season) and May 2, 1995 (longday season) at a minimum night temperature of 20°C in greenhouse. When cotyledons expan-ded, seedlings were transferred in phytotron.  There were 30 – 40 plants were grown in seeding box. There were 3 seedling boxes each plot.  After the leaf number seven or eight opened, the seed-lings were divided into 3 plots, each consisting of 60 or 90 plants per plot.  A 10 mL per plant of 100 ppm GA or 1000 ppm SADH solution were sprayed at 1-week intervals for 3 to 4 times.

          The morfology of floral stage (Yulian, 1994) on shoot tips were observed under a stereoscopic microscope were recorded.  The experiment was stopped when the capitulum of all plots formed on April 18 under natural shortday, and on July 3 under longday season.

 

RESULTS AND DISCUSSION

 

Experiment 1

 

The performance of the plants at the beginning of the plant growth regulators treatment are good health, have 8 full developed fresh green leaf. The plants were found usually treated at 30 days after sowing under shortday season.  The all cultivars trated at the same time due to almost the same growth stage were found when the treatment began. In the previous work, the plant growth habit was described and published.  We consider that in this stage when the plant has about 8 leaves are still on their juvenile stage already.  During the period of this stage the plant is thought to be have a good response with such as inductive condition. Flowering of garland chrysanthemum had been strongly affected with plant growth regulators treatment.  In both cultivar  Hakata Kairyou Chuuba and Kouji Ooba budding of all treatment occurred 100%, respectively (Table 1).  But percentage of budding of Hakata  Kairyou Chuuba under shootday season was higher only when the plant treated with GA₃.  There is a cultivar difference on flowering under plant growth regulator treatment. Some cultivars, i.e. Tasunami, Hakata kairyou chuuba, and Kouji Ooba seems to be very sensitive to the treatment, however, it was not clear yet on such as Otafuku. Treatment.  There is a poor budding occurred under shortday in Kabuhari chuuba treated with 50 ppm GA.  Also in Hakata kairyou chuuba control plants, 100 ppm GA₃ and 1000 ppm SADH treated plants.  But no budding occurance for the other cultivars such as Tatsunami, Kabuhari and Otafuku.

 

Tabel  1.    Effects of plant growth regulators on flowering of

6 different cultivars. 

Cvs.	Treatment	Daylength	Budding(%)	Date of buding
A	Control GA         50ppm GA       100ppm SADH1000ppm Control GA         50ppm GA        100ppm SADH 1000ppm	Longday       Shortday	87.7 100 100 85.7      - - - -	Jun 23 Jun 22 Jun 17 Jun 29 - - - -
B	Control	Longday	100	Jun 25
	GA         50ppm		100	Jun 15
	GA       100ppm		100	Jun 15
	SADH1000ppm		100	Jun 19
	Control	Shortday	12.5	Dec 5
	GA         50ppm		50	Nov 29
	GA       100ppm		37.5	Nov 2
	SADH1000ppm		12.5	Dec 2
C	Control	Longday	87.5	Jun 27
	GA         50ppm		100	Jun 21
	GA       100ppm		100	Jun 21
	SADH1000ppm		100	Jul 5
	Control	Shortday	-	-
	GA         50ppm		12.5	Nov 26
	GA       100ppm		-	-
	SADH1000ppm		-	-
D	Control	Longday	100	Jun 30
	GA         50ppm		57.1	Jun 22
	GA       100ppm		85.7	Jun 26
	SADH1000ppm		85.7	Jul 10
	Control	Shortday	-	-
	GA         50ppm		-	-
	GA       100ppm		-	-
	SADH1000ppm		-	-
E	Control	Longday	100	Jun 2
	GA         50ppm		57.1	Jun 30
	GA       100ppm		85.7	Jul 7
	SADH1000ppm		85.7	Jul 4
	Control	Shortday	-	-
	GA         50ppm		-	-
	GA        100ppm		-	-
	SADH1000ppm		-	-
F	Control	Longday	100	Jun 12
	GA          50ppm		100	Jun 11
	GA        100ppm		100	Jun 11
	SADH1000ppm		100	Jun 13
	Control	Shortday	100	Nov 14
	GA         50ppm		100	Nov 9
	GA       100ppm		100	Nov 9
	SADH1000ppm		100	Nov 21

Cultivar name = A: Tatsunami. B: Hakata kairyou chuuba. C: Kabuhari. D. Kabuhari chuuba. E. Otafuku. F. Koji Ooba.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1. Effects of GA₃ and SADH on capitulum initiation and development

 

Experimen 2

Effects of GA₃ and SADH on capitulum initiation and development under natural shortday season 15°C was shown in Figure 1A.  The floral stages of control, 100 ppm GA₃ and 2000 ppm SADH plots in 15°C during short day season were early involucre-forming stage, late involucre-forming stage, and dome-forming stage, respec-tively on March 21.  But, they were late floret-forming stage, early corolla-forming stage, and late floret-forming stage, repectively in 15°C during longday season (Figure 1D).

In 20°C plot under natural shortday season, the floral stages of control, 100 ppm GA₃, and 1000 ppm SADH plots were early corolla-forming stage, intermediate corolla-forming stage, and early involucre-forming stage, respectively on April 28 (Figure 1B).  But, the floral stage were late in-volucre-forming stage, late involucre-forming stage, and dome-forming stage, respectively in 20°C during longday season on July 3 (Figure 1E).

The flower stages of control, 100 ppm GA, and 1000 ppm SADH plots in 25°C during shortday season were late involucre-forming stage, late involucre-forming stage and late involucre-forming stage, repectively on April 28 (Figure 1C).  But, the floral stages were interme-diate corolla-forming sage, late corolla-forming stage, and early involucre-forming stage, respectively in 25°C during long day season on July 3 (Figure 1F). There was no different of nodes number among treatment in both during short or longday season.  But, although the number of nodes in 15°, 20°, and 25°C under shortday season were increased higher  than control, during longday season in 25°C plot especially, the number of nodes was slightly increased, and then it was increased by the SADH treatment (the datas were not shown).

 

CONCLUSION

 

          Flower bud of GA₃ treated plant occurred earlier than that of control plant, however, budding of SADH treated plant was slightly delayed. In more detail, the capitulum initiation  was promoted by GA₃, and it was delayed by SADH treatment. The capitulum developments were promoted during longday than that shortday season.

 

LITERATURE CITED

 

Fontes, M.R. and J. L. Ozbun. 1970. Effects of growth retardants on growth and flowering of broccoli.  HortScience 5 (6) : 483–484.

Fujime, Y.  1988. Photothermal induction of flower head formation in broccoli plants. J. Jap. Soc. Hort. Sci. 57(1): 70-77 (In Japanese).

Iwami, N., Y. Takahashi, E. Kosuge and S. Kurihara, 1983. Studies on flower bud differentiation and the bolting in some economic green vegetables. Bull. Tokyo Metropolitan Agr. Exp. Sta. 16:1-62.

Javier, E.Q. 1990. In vegetable production manual. (ed. By Javier, E.Q.) Asian vegetable Re-search and Development Centre, Taipei. P. 63

Kobayashi, K. and F. Matsuda. 1975. Studies on flower bud initiation of garland chrysan-themum. Tech. Bull. Senior High School Tokyo Univ. Ed. 14: 7-11 (In Japanese).

Mochizuki, N. and T. Hiraoka. 1978. Studies on internode elongation of garland chrysanthe-mum: I. Effect of photoperiod on internode elongation and flower bud differentiation. II. Effect of GA application on internode elongation and flower bud differentiation. Bull. Kanagawa Agr. Exp. Sta. 120: 1-13.

Suge, H. and H. Takahashi. 1981. The role of gibberellin in thestem elongation and flowering of Chinese Cabbage, Brassica campestris var. pekinensis in their relation to vernalization and photoperiod. Rep. Inst. Agr. Res. Tohoku Univ., 33 : 15 – 34.

Suge, H. 1984. Re-examination on the role of vernalizationand photoperiod in the flowering of Brassica crops under controlled environ-ment.  Japan. J. Breed., 34: 171–180.

Suge , H. and L. Rappaport. 1968. Role of gibberellins in stem elongation and flowering in radish.  Plant Physiol. 43 : 4208 – 1214.

Suzuki, H. 1977. Year-round stable production using protected environment of Kabuhari chuuba for roguing harvesting system. In Outline of Agricultural Technique, Vege-table-7 (ed. By Suzuki, H.). Noubunkyou, Tokyo. p 29-36 (In Japanese).

Yulian, Fujime, Y. and Okuda, N. 1994. Flower bud development and branching property of garland chrysanthemum (Chrysanthemum coronarium L.) J. Jap. Soc. Hort. Sci. 63 (Suppl. 1) : 326 – 327 (in Japanese).

Tsukamoto, Y. and K. Kobayashi. 1959. Studies on vernalisation of growing plant of radish. Mem. Res. Inst. Food. Sci. Kyoto Univ. 18: 41-47.