Effect of phosphorus sources and mycorrhizal infection on growth of in vitro coffee plantlets

anglais. Biofertilizer application by using mycorrhizal fungus has an important role in obtaining high efficiency of P fertilizer and to decrease environmental pollution caused by chemical fertilizers. Symbiosis between plant roots and vesicular-arbuscular (VA)-mycorrhizal fungi may significantly increase soil phosphate uptake and several other nutrients. Mycorrhizae has an important role in enhancing growth, P and Zn uptake and subsequently the efficiency of P fertilizer on coffee. Factor that affect in vitro inoculation (early infection) is antagonistic microorganism present in medium. In vitro mycorrhizal infection on perennial crops is seldom reported, especially for coffee. The aim of this research is to study the influence of phosphorus sources and mycorrhizal infection on growth of in vitro coffee plantlets. This research was conducted in Tissue Culture Laboratory of Indonesian Coffee and Cocoa Research Institute. This experiment was arranged in randomized complete design, consisted of 11 treatments with 3 replications. The basic medium used was modified Murashige and Skoog (MS). Treatments were A. medium only (control), B. medium + mycorrhizae, C. medium + 85 mg KH2PO4/l + mycorrhizae, D. medium + 170 mg KH2PO4/l + mycorrhizae, E. medium + 75 mg NaH2PO4/l + mycorrhizae, F. medium + 150 mg NaH2PO4/l + mycorrhizae, G. medium + 75 mg Ca-phytate/l + mycorrhizae, H. medium + 150 mg Ca-phytate/l + mycorrhizae, I. medium + 85 mg KH2PO4/l + 75 mg Ca-phytate/l + mycorrhizae, J. medium + 75 mg NaH2PO4/l + 75 mg Ca-phytate/l + mycorrhizae, K. medium + 85 mg KH2PO4/l + 75 mg NaH2PO4/l + 75 mg Ca-phytate/l + mycorrhizae. A mycorrhizae fungus, Gigaspora margarita, and coffee clone of BP 42 were used in this experiment. Result of this experiment showed that there was no effect of P addition as well as mycorrhizal infection on the growth of in vitro plantlets of coffee. Mycorrhizal infection on plantlets grown on single source of P medium was higher than that on medium with combination of P sources. The infection was characterized by growing hyphae and vegetative spores developed around the coffee root plantlets

indonésien. Penelitian pengaruh sumber fosfor (P) dan infeksi jamur mikoriza terhadap pertumbuhan planlet kopi secara in vitro telah dilakukan di Laboratorium Kultur Jaringan Pusat Penelitian Kopi dan Kakao, Jember. Sumber P yang digunakan meliputi KH2PO4, NaH2PO4, Ca-phytate dan kombinasi antar ketiga senyawa tersebut. Hasil penelitian menunjukkan bahwa penambahan P dan mikoriza tidak mempengaruhi pertumbuhan planlet kopi. Infeksi mikoriza pada planlet yang ditanam pada medium dengan sumber P tunggal lebih efektif dibandingkan pada medium dengan kombinasi sumber P. Terjadinya infeksi ditandai dengan pertumbuhan hifa, sporocarp dan spora vegetatif yang berkembang di sekitar jaringan akar