Effects of Fertilizer Formulations on Flowering of Doritaenopsis I-Hsin Madame in Gradational Nutrition Management

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1 Effects of Fertilizer Formulations on Flowering of Doritaenopsis I-Hsin Madame in Gradational Nutrition Management K.-H. Chang, R.-Y. Wu, and T.-F. Hsieh a Floriculture Research Center Taiwan Agriculture Research Institute Council of Agriculture Yun Lin Taiwan, ROC Keywords: nitrogen, orchids, Phalaenopsis, phosphorus, potassium, reproductive growth, spike induction Abstract Previous reports showed that an increase in phosphorous (P) application did not stimulate spike induction and flowering of Phalaenopsis when potassium (K) application was sufficient, whereas an increase in nitrogen (N) application promoted flowering. However, excessive N concentrations could prolong the time required for anthesis of Phalaenopsis. The objective of this research was to determine effects of different formulations of fertilizers with gradational nutrition management on the flowering of Doritaenopsis (Dtps.) I-Hsin Madame. Compared to the invariable nutrition management, plants of Dtps. had higher spike emergence rates, faster growth of flowering spikes and earlier anthesis under the gradational nutrition management of fertilizer, (N-P 2 O 5 -K 2 O) or (N-P 2 O 5 -K 2 O). At the same level of K application, higher amounts of N application accelerated the growth of flowering spikes and increased number of flowers on each plant. Although growth of Dtps. Spikes was dependent upon supply of the N fertilizer, increased amount of N application resulted in decreased width of flower petals. This study suggests that decreased petal width may be due to an imbalance of N and K uptake by the plant or insufficient amount of carbon accumulation in the flower. INTRODUCTION Doritaenopsis (Dtps.) is an intergeneric hybrid of Doritis and Phalaenopsis (Phal.), which is a typical CAM (crassulacean acid metabolism) plant (Osmond, 1978). The market demands for Dtps. are strong because the plants have a long flowering period and a variety of flower colors and shapes (Wang and Lee, 1994; Griesbach, 1995). The quality and quantity of fertilizers are main factors affecting growth and development of Phal. and Dtps (Cui et al., 2004; Poole and Seeley, 1978; Yoneda et al., 1997). Plants in deficiency of phosphorus (P) take longer to anthesis (Rossiter, 1978) and reduce number of flowers (Bould and Parfitt, 1973). Sufficient amount of P fertilizer promotes flowering of orchids (Arditti, 1992), whereas inadequate amount of P fertilizer delays the spiking of Phal. (Yoneda et al., 1997). However, Wang (2000) reported that the concentration of P increased to higher than 44 mg/l was not beneficial for spiking and flowering of Phal. An appropriate increase in nitrogen (N) and potassium (K) fertilizers promoted flowering (Wang, 2000, 2007), whereas excessive amount of N fertilizer delayed spiking of Phal. (Duan and Yazawa, 1995; Gordon, 1989; Ichihashi, 2003; Kubota et al., 1991). A compound fertilizer ( ; N-P 2 O 5 -K 2 O) is commonly used by growers to manipulate the flowering of Dtps. in Taiwan. However, there were distinct effects of the components in the nutrient solution between spike induction and inflorescence development of Phal. (Ichihashi, 2003; Kubota et al., 1991; Wang, 2000). In addition, the rate of N, P, and K fertilizers was important on the uptake of nutrients by the plant due to competition and antagonism between nutrient ions. Therefore, the objective of this study was to determine effects of the fertilizer formulations with gradational nutrition a TFHsieh@tari.gov.tw Proc. I st Int l Orchid Symposium Eds.: M.G. Blanchard et al. Acta Hort. 878, ISHS

2 management on the spike induction and inflorescence development of Dtps. I-Hsin Madame. MATERIALS AND METHODS Plant Materials and Growing Conditions A total of 192 plants of a red flowered Dtps. I-Hsin Madame was used in this study. The plants were mature and uniform with average leaf span of 37.3 cm and leaf number of 5.6. They were planted in plastic pots (10.5 cm in diameter) containing 560 ml of Chilean sphagnum moss (Jenn-yioung company, Taichung, Taiwan), 1 plant per pot. The experiment was conducted in a forcing greenhouse with glass panels on the roof and sides from Sept to Jan under natural photoperiod. During the experimental period, the conditions of this glasshouse were 25/20 C for maximum day/night temperatures, 10.5 to 12.0 h for day length, and 275 to 475 µmol m -2 s -1 for photosynthetically active radiation (PAR). Experimental Design After receiving a continue supply of a nutrient solution containing (N-P 2 O 5 -K 2 O) fertilizer for 30 d, the plants of Dtps. were then divided into four treatments of different fertilizer formulations for the rest of the experimental period of 150 d. The rates of N-P 2 O 5 -K 2 O for the four fertilizers were , , , and All treatments were arranged in a randomized complete block design with four replicates, 12 plants per replicate. The experiment was repeated once. For the 150-d period, the plants in each treatment were irrigated with nutrient solution every three weeks at 250 ml/plant. The nutrient solutions of all treatments were prepared by dissolving various fertilizers in tap water and adjusting the concentration of fertilizers to 1.0 g/l. The composition of macronutrients in tap water and various nutrient solutions are presented in Table 1. Plant Growth Measurements The number of plants of Dtps. with initial flowering spikes in each treatment was recorded at 22, 28, 34 and 40 d after forcing treatment. The growth of flowering spikes was determined by measuring length of each initial spike from the base to the tip at 40, 60, 85, 100 and 150 d after forcing treatment. Flowering characteristics were determined by counting numbers of flowers per plant, time to flowering, and width of first to fifth flowers on earlier initial spikes at the end of the experiment. At the end of the experiment, eight plants in each treatment were sampled for plant analysis of macronutrients. The macronutrients composition (C, N, P, and K) of flowering spikes and flowers per plant were determined using published procedures (AOAC, 1970, 2006; Yoshida, 1972). RESULTS AND DISCUSSION Effects of Fertilizer Formulations on Spiking, Spike Length and Time to Anthesis in the Gradational Nutrition Management There was no significant difference in the spiking of the earlier initial spike of Dtps. among all treatments during the initial stage (30 d after forcing treatment) of the gradational nutrition management (data not shown). Wu et al. (2009) reported that an increase of N supply delays the spiking of Dtps. I-Hsin Madame in invariable nutrition management during the initial stage (30 d after forcing treatment). The higher amount of N application delays the spiking of Dtps. I-Hsin Madame is similar to previous reports of Phal. (Duan and Yazawa, 1995; Gordon, 1989; Ichihashi, 2003; Kubota et al., 1991; Wang, 2000). Thus, it is obvious that the gradational nutrition managements of to , and does not delay the spiking, compared to the plants grown under the invariable nutrition management. There was no significant (P>0.05) difference in the length of earlier initial spikes 348

3 among all the treatments at 85 d after forcing treatment (Table 2). However, the length of earlier initial spikes of the plants in the fertilizer treatment of was longer than those plants in the treatments of and fertilizers during 60 d after forcing treatment (Wu et al., 2009). Thus, the gradational nutrition management also promotes growth of flowering spikes of Dtps. by the fertilizer treatment of , or , compared to the invariable nutrition management. The spiking of the plants in all fertilizer treatments under the gradational nutrition management was uniform in the time of spiking; therefore, the influence of forcing treatments of different fertilizer formulations on the growth of flowering spikes was not distinct during the initial stage (85 d of forcing) of the experiment. Under gradational nutrition management, the time to anthesis for plants of Dtps. treated with the fertilizer of was longer than that treated with or (Table 3). However, there were no significant (P>0.05) differences among the treatments of , and (Table 3). Under invariable nutrition management, plants received the and treatments took longer to anthesis than those treated with water or fertilizer (Wu et al., 2009). Therefore, plants grown under the treatment of or had an earlier anthesis, compared to the invariable nutrition management. Cui et al. (2004) reported that the time to anthesis of Dtps. increased in response to an increase in the concentration of nutrient solution. In addition, Wang (2000) and Ichihashi (2003) indicated that an excess of N supply delays the spiking of Phalaenopsis; however, the time to anthesis of Phalaenopsis was unaffected by different P or K concentrations (Wang, 2000, 2007). Therefore, the delayed anthesis of Dtps. by the treatment of or under invariable nutrition management may be due to excessive amounts of N fertilizer in the nutrient solution. Plants treated with the fertilizer of or had an earlier anthesis under gradational nutrition management. This indicates that application of low N fertilizer during the initial 30-d after forcing treatment may have triggered early anthesis of Dtps. Nishimura et al. (1971) reported that initiation of flower induction of Dtps. was when the spike length was about 1 to 4 cm. Therefore, it is possible that the shorter time to anthesis is due to earlier spiking and rapid increase of spike length to about 1 to 4 cm under the gradational nutrition management. In addition, the earlier flower induction might cause the plants to advance for the floral evocation and development. Effects of Fertilizer Formulations on Spike Growth and Petal Width The total spike length of plants of Dtps. in the fertilizer treatments of and was longer than plants in the treatment of (Table 3). Similarly, the total spike length of plants treated with fertilizer was longer than the spike length of plants treated with or in invariable nutrition management (Wu et al., 2009). Wang and Gregg (1994) indicated that the spike length of Phalaenopsis increased in response to an increase in the concentration of nutrient solution. In addition, the increase of N supply promoted growth of flower spikes (Wong and Chua, 1975). At the end of the experiment, the N concentration of flower spikes in the fertilizer treatment of was the highest among all treatments and the carbon to nitrogen ratio (C/N ratio) of this treatment was lower than the treatments of and (Table 5). The amount of N accumulated in flowering spikes from the treatment was the highest among all treatments (Table 5). These results suggest that the growth of spikes of Dtps. is depending on the amount of N fertilizer in the nutrient solution. Therefore, increased amount of N fertilizer in the nutrient solution at the entire reproductive period is beneficial to the growth and development of spikes of Dtps. The number of flowers per plant of Dtps. increased with an increase of N rate in the fertilizer compound (Table 3). Cui et al. (2004) and Wang and Gregg (1994) reported that the number of flowers of Dtps. and Phalaenopsis increased with an increase of strength in the nutrient solution. The result also showed that an increase of P in the nutrient solution did not increase total number of flowers on each plant at the same level 349

4 of K application (Table 3). This finding on Dtps. is similar to the report of Wang (2000) on Phalaenopsis. Furthermore, the width of flower petals of Dtps. decreased when the plants received high amount of N (Table 4). This result is similar to the report of Cui et al. (2004) that the width of flower petals decreased as the number of flowers increased. Among treatments of , and tested at the end of the experiment, the concentration of N in Dtps. flowers was the highest for the treatment of (Table 5). However, there was no significant difference in the C/N ratio among these three treatments (Table 5). In addition, the concentration of K in the flower from the treatment of was lower than the flower from the treatments of and (Table 5). The amount of N accumulated in the flower from the treatment of was higher than the flower from the treatments of and (Table 5). However, there was no significant (P>0.05) difference in the amount of C accumulated in the flower from the treatments of , and The amount of K accumulated in the flower from the treatment of was lower than the flower from the treatments of and (Table 5). These results suggest that reduction in width of flower petals of Dtps. may be due to imbalance of N and K uptake or insufficient amount of C accumulated in the flower. CONCLUSIONS This study reveals that, compared to plants grown in invariable nutrition management, the gradational nutrition management is a useful method for growing Dtps. because the plants have higher emergence rate of spikes, faster growth rate of flower spikes and earlier anthesis. The study also indicates that the growth of spikes of Dtps. is associated with application rate of N fertilizer. However, increased N application resulted in decreased width of flower petals due to imbalance of N and K uptake by the plant or the insufficient amount of C accumulation in the flower. ACKNOWLEDGEMENTS The authors would like to express their gratitude to Dr H. C. Huang, emeritus Principal Research Scientist, Agriculture and Agri-Food Canada, Research Centre, Lethbridge, Alberta, Canada, for critical review and criticisms of this manuscript. Literature Cited Association of Official Analytical Chemists Official Methods of Analysis. 12th ed. AOAC, Washington, DC. Association of Official Analytical Chemists Official Methods of Analysis, 18 th ed. AOAC, Washington, DC. Arditti, J Flowering. p In: J. Arditti (ed.), Fundamentals of Orchid Biology. Wiley, New York, USA. Bould, C. and Parfitt, R.I Leaf analysis as a guide to the nutrition of fruit crops. X. Magnesium and phosphorus sand culture experiments with apple. J. Sci. Food Agri. 24: Cui, Y.Y., Jeon, M.W., Hahn, E.J. and Paek, K.Y Concentration of nutrient solution and growing media affect growth and flowering of Doritaenopsis Tinny Tender. Acta Hort. 644: Duan, J.X. and Yazawa, S Floral induction and development in Phalaenopsis in vitro. Plant Cell Tiss. Org. Cult. 43: Gordon, B Phalaenopsis flower induction (or, How to make them bloom). Amer. Orchid Soc. Bull. 58: Griesbach, R.J A Phalaenopsis in every pot. Orchid Dig. 59: Ichihashi, S Effect of nitrogen application on leaf growth, inflorescence development and flowering in Phalaenopsis. Bull. Aichi Univ. Edu. 52: Kubota, S., Asai, S. and Yoneda, K The effect of the timing of nitrogen application on the growth and flowering of Phalaenopsis. J. Japan. Soc. Hort. Sci. 60: (in Japanese) 350

5 Nishimura, G., Kosugi, K. and Hurukawa, J Studies on the flower formation of orchids. II. Flower formation and development of Phalaenopsis. Proc. Mtg. Japan. Soc. Hort. Sci. p (in Japanese) Osmond, C.B Crassulacean acid metabolism: a curiosity in context, Ann. Rev. Plant Physiol. 29: Poole, H.A. and Seeley, J.G Nitrogen, potassium and magnesium nutrition of three orchid genera. J. Amer. Soc. Hort. Sci. 103: Rossiter, R.C Phosphorus deficiency and flowering in subterranean clover (Tr. Subterraneum L.). Ann. Bot. 42: Wang, Y.T Impact of a high phosphorus fertilizer and timing of termination of fertilization on flowering of a hybrid moth orchid. HortScience 35: Wang, Y.T Potassium nutrition affects Phalaenopsis growth and flowering. HortScience 42: Wang, Y.T. and Gregg, L.L Medium and fertility affect the performance of Phalaenopsis orchids during two flowering cycles. HortScience 29: Wang, Y.T. and Lee, N A new look for an old crop: Potted blooming orchids. Greenhouse Grower 12: Wong, Y.K. and Chua, S.E Yield and growth responses of Aranda Wendy Scott to manorial treatments with NPK and sawdust mulch. Singapore J. Primary Ind. 3: Wu, R.I., Din, I., Hsieh, T.F., Dai, T.E. and Chang, K.H Effects of fertilizer formulations and invariable and gradational nutrition management on the flowering of Doritaenopsis I-Hsin Madame. J. Taiwan Soc. Hort. Sci. 55: (in Chinese with English abstract) Yoneda, K., Usui, M. and Kubota, S Effect of nutrient deficiency on growing and flowering of Phalaenopsis. J. Japan. Soc. Hort. Sci. 66: (in Japanese with English summary) Yoshida, S Laboratory Manual for Physiological Studies of Rice. IRRI, Los Banos. Tables Table 1. The composition of macronutrients in tap water and various nutrient solutions used in the experiment of Doritaenopsis I-Hsin Madame. Concentration (mg/l) Solution z Fertilizer N P K Ca Mg S Tap water Free y N-20P 2 O 5-20K 2 O x N-30P 2 O 5-20K 2 O w N-20P 2 O 5-20K 2 O w N-10P 2 O 5-20K 2 O x z Plants in each treatment received (N-P 2 O 5 -K 2 O) fertilizer dissolved in tap water for the initial 30 days and then changed to the different fertilizer compounds for the rest of the experiment period of 150 days. y Not determined. x Fertilizers developed and manufactured by FRC, TARI (Floriculture Research Center, Taiwan Agriculture Research Institute). The components of NH 4 + -N, NO 3 - N, and urea were 1.5, 3.5 and 0%, respectively, in 5N-20P 2 O 5-20K 2 O and 8.8, 11.1 and 10.1% in 30N-10P 2 O 5-20K 2 O. w Peters (Scotts company, Marysville, Ohio, USA). The components of NH 4 + -N, NO 3 - -N, and urea were 4.9, 5.1 and 0%, respectively, in 10N-30P 2 O 5-20K 2 O and 3.8, 6.1 and 10.1% in 20N-20P 2 O 5-20K 2 O. 351

6 Table 2. Effect of gradational nutrition management on length of flower spikes of Doritaenopsis I-Hsin Madame. Fertilizer z Length of earlier spike (cm) 40 d 60 d 85 d 100 d 150 d a y 39.7 a 67.1 a 74.3 b 79.8 b a 42.3 a 73.7 a 89.8 a 98.8 a a 44.2 a 77.1 a 91.3 a 97.4 a a 41.1 a 74.4 a 90.1 a 90.9 a z Plants in each treatment received (N-P 2 O 5 -K 2 O) fertilizer dissolved in tap water for the initial 30 days and then changed to the different fertilizer compounds for the rest of the experiment period of 150 days. y Means within each column followed by the same letter are not significantly (P 0.05) different according to Duncan s multiple range test. Table 3. Effect of gradational nutrition management on the flowering of Doritaenopsis cultivar I-Hsin Madame z. Fertilizer y Time to anthesis Spike length No of flowers per plant (d) (cm per plant) c x 100 b 92.5 b b 107 b ab b 110 ab a a 128 a a z Data collected at the end of the experiment (150 days). y Plants in each treatment received (N-P 2 O 5 -K 2 O) fertilizer dissolved in tap water for the initial 30 days and then changed to the different fertilizer compounds for the rest of the experiment period of 150 days. x Means within each columns followed by the same letter are not significantly (P 0.05) different according to Duncan s multiple range test. Table 4. Effect of fertilizer formulations on the petal width of earlier initial spike of Doritaenopsis I-Hsin Madame. Flower width (cm) y Fertilizer z 1 st 2 nd 3 rd 4 th 5 th a x 10.3 a 9.5 a 9.5 a 9.8 a a 10.5 a 9.4 a 9.6 a 9.4 a a 10.2 a 9.6 a 9.4 a 9.0 b b 9.6 b 8.7 b 8.8 b 8.0 c z Plants in each treatment received (N-P 2 O 5 -K 2 O) fertilizer dissolved in tap water for the initial 30 days and then changed to specific fertilizer formulations for the rest of the experiment period (150 days). y Data collected at the end of the experiment (150 days). x Means within columns followed by the same letter are not significantly (P 0.05) different according to Duncan s multiple range test. 352

7 Table 5. Effect of fertilizer formulations on the concentration (g/kg) and amount of N, P, and K and C/N ratio of flowering spikes and flowers of Doritaenopsis I-Hsin Madame. Fertilizer z N, N C, P, P, K, K, C/N (g/kg) (mg) (mg) (g/kg) (mg) (g/kg) (mg) Flowering spike y c x 20.4 d z 55.0 a 1121 c 2.1 a 5.0 b 43.2 a c c 38.8 c 44.9 b 1513 b 2.1 a 8.0 a 43.7 a a b 56.1 b 27.5 c 1541 b 2.8 a 9.5 a 39.6 ab b a 84.0 a 21.2 c 1775 a 2.3 a 9.2 a 35.2 b b Flower y c x 30.4 c 26.8 a 813 b 3.8 b 7.2 b 63.3 a b b 45.8 b 21.9 b 999 a 4.6 a 10.6 a 67.7 a a b 51.5 ab 21.2 b 1083 a 4.5 a 11.3 a 57.3 ab a a 54.3 a 18.4 b 1037 a 4.3 a 9.9 ab 53.9 b b z Plants in each treatment received (N-P 2 O 5 -K 2 O) fertilizer dissolved in tap water for the initial 30 d and then changed to specific fertilizer formulations for the rest of the experiment period (150 days). y Data collected at the end of the experiment (150 days). z Means within each column followed by the same letter are not significantly (P 0.05) different according to Duncan s multiple range test. 353

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