Effect of Nitrogen and Potassium on Growth and Development of Curcuma alismatifolia Gagnep. S. Ruamrungsri, C. Suwanthada N. Ohtake, K. Sueyoshi and T. Ohyama and P. Apavatjrut Department of Applied Biological Chemistry Department of Horticulture Faculty of Agriculture Faculty of Agriculture Niigata University Chiang Mai University Ikarashi 2-8050, Niigata Chiang Mai 50200 Japan Thailand Keywords: plant nutrition, Siam tulip, Curcuma alismatifolia Abstract Stubbed rhizomes (without storage root) of Curcuma alismatifolia Gagnep. were planted in soilless medium using sand + rice husk charcoal at the ratio 1:1 (v:v). After shoot sprouting, plants were fertilized with different nutrient solutions three times a week. Three levels of N (50, 100 and 200 mg l -1 ) combined with three levels of K (50, 100 and 200 mg l -1 ) were investigated. The results showed that the nitrogen concentration at 200 mg l -1 gave the highest results in plant height, number of plants/cluster, diameter of new rhizome, number of new rhizomes, the length of storage root and flower quality. The different levels of potassium tested did not affect these parameters excepted for the number of green bracts and vase life. The optimal levels of nitrogen and potassium for Curcuma alismatifolia Gagnep. growing in the soilless medium was each at 200 mg l -1. INTRODUCTION Curcuma alismatifolia Gagnep. is a member of the tribe Hedychieae in the family Zingiberaceae. Its origin is diverse in tropical countries from Australia, Asia and Africa and is found about 30 species in Thailand (Patumma, 2004). It is called Patumma, Siam Tulip or Chiang Mai Pink and has become an important flower bulb crop in Thailand, and is also widely known in various overseas markets. Its colorful bract and long lasting flower is suitable for both cut flower and pot plant. In 1998, Thailand exported approximately 500,000 rhizomes to Japan, the amount of 350,000 and 80,000 rhizomes to the Netherlands and USA, respectively (Amazing Tropical Flower, 1999). Main production areas are in Chiang Mai, Chiang Rai, Lumpun and Payao. Growing C. alismatifolia in soil can result in disease problems caused by the soil-borne pathogen Ralstonia solanacearum. Growers have changed cultivation methods, using soilless culture, in an attempt to produce good quality rhizome and prevent infection by R. solanacearum. Ruamrungsri and Apavatjrut (2003) reported that nutrient deficiency affected growth of this curcuma in soilless culture. The objective of this study was to identify the optimal levels of nitrogen and potassium for growing curcuma plants in soilless culture. MATERIALS AND METHODS Stubbed rhizomes without storage roots were planted in soilless medium using sand + rice husk charcoal at the ratio 1:1 (v:v) under a rainproof house. After sprouting, they were fed with different nutrient solutions comprising different levels of nitrogen and potassium. Three levels of nitrogen i.e. 50, 100 and 200 mg l 1 combined with three levels of potassium i.e. 50, 100 and 200 mg l -1. Each nutrient solution treatment also contained P 50, Ca 65, Mg 20, B 0.22, Mn 0.54, Zn 0.26, Mo 0.04 and Fe 0.45 mg l 1. The plants were fed with different solution treatments once a week (3 l m -2 ). Plant growth, flower quality and rhizome yield were determined. The experimental design was a completely randomized design with 3 x 3 factorial treatments, 4 replicates per treatment (5 plants/rep.). Proc. IX th Intl. Symp. on Flower Bulbs Eds.: H. Okubo, W.B. Miller and G.A. Chastagner Acta Hort. 673, ISHS 2005 443
RESULTS AND DISCUSSION The stubbed rhizomes (without storage roots) planted in soilless culture sprouted at 47 days after planting. The effects of nitrogen and potassium levels in the nutrient solutions were shown as follows: Plant Growth The results showed that nitrogen level at 200 mg l -1 gave better plant height despite different K levels (Table 1, Fig. 1) and number of plants/cluster, especially when 200 mg l -1 K was also added (Table 1, Fig. 2). In contrast, plant height and number of plants/cluster decreased in treatments with nitrogen level at 50 mg l -1. Nitrogen supply also affected number of leaves/plant, not withstanding, potassium supply did not significantly affect growth parameters of this curcuma. Flowering and Flower Quality Flower quality attributes such as peduncle length, number of pink bracts, number of green bracts and vase life declined in low nitrogen treatments (Table 2, Fig. 3). Peduncle length was 34-36 cm in the treatment supplied with N 200 mg l -1 and higher than those obtained from the other treatments. However, the number of pink bracts from the treatments combined with 100 mg l -1 N was not significantly different from the 200 mg l -1 N treatments. In addition, when both nitrogen and potassium were combined, each at 200 mg l -1, it gave the highest number of green bracts. Nitrogen levels also affected flowering dates (Table 2), indicating that an optimal level of nitrogen supply was involved in stimulating vegetative tissue formation to occur earlier, when the leaf formation reached a minimum leaf number (i.e. 4 leaves). When the leaves were well developed, flower bud initiation subsequently occurred. The optimal nitrogen supply, therefore, indirectly enhanced early flowering. However, the time or form of nitrogen application or both of these factors have been reported to affect flower formation more than by the level of nitrogen supply and the effects of mineral nutrient supply on flower formation are brought about by changes in phytohormone level (Marschner, 1995). In this experiment, nitrogen level did not effect flower formation but decreased flower quality. Potassium supply did not effect growth parameters in general, except for the number of green bracts and vase life (Table 2). Rhizome Quality and Yield After dormancy, plants were harvested then rhizome quality attributed i.e. diameter, the number of storage roots/rhizome, length of storage root were measured. In general, a high nitrogen supply is important for rapid leaf expansion and for obtaining an optimum LAI, a value considered necessary for high tuber yields (Marschner, 1995). The results showed that high level of nitrogen increased fresh weight of new rhizomes, rhizome diameter, number of storage roots/rhizome, length of storage roots and number of rhizomes/cluster at harvest (Table 3). In a previous report, we found that from the beginning to the end of the dormant period, the accumulated nitrogen as original nitrogen (nitrogen is already stored in rhizome and storage root before additional N is taken up) of Curcuma alismatifolia gradually decreased and it was used for bud sprouting and growth in next season (Ruamrungsri et al., 2001). The effect of nitrogen levels in this experiment indicated that the original nitrogen in planted rhizome is not sufficient to supply nitrogen during the full growth period. Therefore the addition of optimal N is necessary for growth and development of curcuma. Similar results were also found in Narcissus and plants absorbed a large amount of nitrogen during the growing period and accumulated in the new scale for the next crop (Ruamrungsri et al., 1996, 1997). Previous reports showed that lack of potassium caused a decrease in rhizome fresh weight, rhizome diameter and the length of storage root (Ruamrungsri and Apavatjrut, 2003). However, the different levels of potassium supply in this experiment did not affect rhizome quality and yield. 444
The combination of nutrient solution with 200 mg l -1 N and 200 mg l -1 K was optimum for growing C. alismatifolia rhizomes without storage roots in the soilless culture in this experiment. ACKNOWLEDGEMENTS We thank H.M. the King s Initiative Centre for Flower and Fruit Propagation, Thailand for supporting plant materials and equipment in this study. Thanks to the Hitachi Scholarship Foundation for financially supporting our presentation in the IXth International Symposium on Flower Bulbs held in Niigata, Japan. Literature Cited Amazing Tropical Flower. 1999. Production Potential and Marketing of Pathumma. Thailand, August, 26-29. p.29-38. Marschner, H. 1995. Mineral Nutrition of Higher Plants. Academic press, New York. 674p. Patumma, 2004. www.doae.go.th/patumma.htm Ruamrungsri, S., Ohyama, T., Konno, T. and Ikarashi, T. 1996. Deficiency of N, P, K, Ca, Mg and Fe mineral nutrients in Narcissus cv. Garden Giant. Soil Sci. Plant Nutr. 42(4):809-820. Ruamrungsri, S., Ruamrungsri, S., Ikarashi, T. and Ohyama, T. 1997. Uptake, translocation and fractionation of nitrogen in Narcissus organs by using 15 N. Acta Hort. 430:73-78. Ruamrungsri, S., Ohtake, N., Sueyoshi, K., Suwanthada, C., Apavatjrut, P. and Ohyama, T. 2001. Changes in nitrogenous compounds, carbohydrates and abscisic acid in Curcuma alismatifolia Gagnep. during dormancy. J. Hort. Sci. & Biotech. 76(1):48-51. Ruamrungsri, S. and Apavatjrut, P. 2003. Effect of nutrient deficiency on the growth and development of Curcuma alismatifolia Gagnep. Proc. 3 rd Symposium on the Family Zingiberaceae, Thailand, July, 7-12. p.98-104. Tables Table 1. Effect of N and K on plant height, number of leaves/plant and number of plants/ cluster at 20 weeks after planting. Treatment N:K levels Height 1 (mg l -1 ) (cm) leaves/plant plants/cluster 1 1 50:50 31.75e 5.90a 2.20 e 2 50:100 33.20cde 5.90a 1.94 e 3 50:200 32.70de 5.90a 2.55 de 4 100:50 34.95abc 5.60ab 3.45 c 5 100:100 35.85ab 5.10b 3.15 cd 6 100:200 34.40bcd 5.70ab 3.30 cd 7 200:50 37.40a 5.20b 4.40 b 8 200:100 36.80ab 5.20b 4.90 b 9 200:200 35.40abc 5.30ab 5.95 a N-effect 2 * * * K-effect 2 ns ns ns 1 Means within the same column followed by different characters showed significant difference between treatments by LSD test at p=0.05. 2 * = Effect of fertilizer levels are significant at p=0.05; ns = not significantly different. 445
Table 2. Effect of N and K on flower quality of Curcuma alismatifolia Gagnep. N:K levels (mg l -1 ) Days to flowering Peduncle length 1 (cm) pink bracts 1 green bracts 1 Vase life (days) 50:50 131.21a 29.21e 9.94c 6.68c 19.57cd 50:100 131.70a 38.27cde 10.40bc 7.05bc 16.00d 50:200 132.10a 29.60de 11.05b 7.30b 20.90c 100:50 129.65a 33.50abc 12.55a 7.20bc 28.35a 100:100 129.50a 32.65bc 12.45a 6.95bc 27.47ab 100:200 129.31a 32.15bcd 12.52a 7.36b 20.15c 200:50 117.20b 34.57ab 12.35a 7.05bc 25.35b 200:100 119.45b 34.40ab 12.30a 7.20bc 21.80c 200:200 113.35b 35.95a 12.50a 8.05a 21.35c N-effect 2 * * * * * K-effect 2 ns ns ns * * 1 Means within the same column followed by different characters showed significant difference between treatments by LSD test at p=0.05. 2 * = Effect of fertilizer levels are significant at p=0.05; ns = not significantly different. Table 3. Effect of N and K on rhizome quality and yield of Curcuma alismatifolia. Treatment N:K levels (mg l -1 ) Rhizome diameters (cm) storage roots/rhizome Length of storage root rhizomes/ cluster 1 1 50:50 1.82b 6.70 13.47de 2.25e 2 50:100 1.85b 7.40 12.82e 2.31de 3 50:200 1.90b 7.10 12.85e 2.42cde 4 100:50 1.89b 8.17 15.30bc 3.05cd 5 100:100 1.88b 7.88 15.19bc 3.11bc 6 100:200 1.93b 7.75 14.60bcd 3.15bc 7 200:50 1.92b 7.25 16.12a 3.85b 8 200:100 2.08a 8.27 17.32a 4.73a 9 200:200 2.12a 7.15 16.92a 5.05a N-effect 2 * * * * K-effect 2 ns ns ns ns 1 Means within the same column followed by different characters showed significant difference between treatments by LSD test at p=0.05. 2 * = Effect of fertilizer levels are significant at p=0.05; ns = not significantly different. 446
Figures Height(cm) 40 35 30 25 20 15 10 5 0 8 10 12 14 16 18 20 Weeks after planting T1 T2 T3 T4 T5 T6 T7 T8 T9 Fig. 1. Curcuma alismatifolia Gagnep. grown in different nitrogen and potassium supplies showing plant height at different stages. Fig. 2. Number of plants/cluster from different levels of N and K. 447
Fig. 3. Flower quality of Curcuma alismatifolia Gagnep. from different levels of N and K. 448