EFFECTS OF NITROGEN SOURCE AND WAVELENGTH OF LED-LIGHT ON ORGANOGENESIS FROM LEAF AND SHOOT TIP CULTURES IN LYSIONOTUS PAUCIFLORUS MAXIM

Effect of nitrogen sources on in vitro culture of Lysionotus pauciflorus Maxim. was investigated using 4 variants of Murashige and Skoog (MS) medium, each with varied nitrogen composition and concentration: MS (1650 mg l(-1) NH4NO3 + 1900 mg l(-1) KNO3), MS3B (825 mg l(-1) NH4NO3 + 995 mg l(-1) KNO3), MS4 (1900 mg KNO3), and MS5 (1900 mg l(-1) KNO3 + 1751 mg l(-1) NaNO3). When leaves were cultured on these variants of medium each containing 1 mg l(-1) BAP and 0.5 mg l(-1) NAA, adventitious shoot regeneration frequencies of MS, MS3B, MS4, and MS5 were 66.7, 53.3, 33.3, and 0%, respectively, and mean number of adventitious shoots was 8.9, 5.0, 0.9, and 0, respectively. When shoot tips were cultured on MS, MS3B, and MS4 without supplementation of any plant growth regulator, they elongated to give node numbers of 4.4 - 4.6, whereas MS5 gave less growth with node number of 2.4. Consequently, means of shoot length were 23.6, 28.7, 27.8, and 4.7 mm in MS, MS3B, MS4, and MS5, respectively. Effect of light quality on in vitro culture of leaf explants was also examined on MS containing 0.5 mg l(-1) NAA in combination with or without 1 mg l(-1) BAP by incubating at 25 2 C under continuous light from light emitting diodes (LEDs) with peak wavelengths of 470 nm (blue), 590 nm (orange), 625 nm (red), and from white LEDs at 40 mu mol m(-2) s(-1) or darkness. Adventitious shoots were regenerated from all leaf explants cultured under LED-light, whereas adventitious shoot regeneration was completely inhibited under the dark condition. The highest number of regenerated shoots was 30.4 when cultured on medium supplemented with 1 mg l(-1) BAP and 0.5 mg NAA under red LED-light. The highest frequency of long adventitious shoot (>5 mm) formation was also obtained under red LED-light. Under orange LED-light, shoot differentiation was suppressed as compared with that under the other peak-wavelength LED-light.