Potensi Bakteri Endofit Penghasil Hormon Asam Indol Asetat dan Pelarut Fosfat dari Rumput Teki (Cyperus rotundus) dalam Meningkatkan Pertumbuhan Tanaman Jagung (Zea mays))

Abstract

Endophytic bacteria have taken much attention because of its potential to promote plant growth. This research wos aimed to isolate endophytic bacteria from grass (Cyperusrotundus) and to examine its potential in producing indole acetic acid (IAA) and in solubilizing phosphate. Isolation of endophytic bacterial was done by surface sterilization and slicing method of sample of roots, stems, and leaves with alcohol and sodium hypochlorite follow by incubating sliced sample in nutrient agar. Growing bacterial colony was characterized for their morphological and simple biochemical characterization. All isolates were examined for their ability to produce IAA and to solubilize phosphate. Three (AZ5, AZ12 and AZ6)out of fifteen isolates indicated to produce IAA and to solubilize phosphate. IAA producing test using spectrophotometer method showed supernatant of AZ5 , AZ12, and AZ6 produce IAA with optical density of 10,27, 9,31 and 5,75 respectively. Phosphate solubilizing test using Pikovskaya showed that the three isolates produc diameter of clear zone of 49.91 μL/mL, 48.18 μL/mL and 44.45 μL/mL respectively. This study showed that some endophytic bacteria from Cyperus rotundus were potentially as phosphate solubilization and plant growth hormone production. The result of the application of endophytic bacterial AZ5, AZ6, AZ12 isolates on corn (Zea mays) was best treatment in AZ5, AZ5+AZ6, and AZ5+AZ6+AZ12 combination against the plant length of corn plant.

Penelitian ini bertujuan untuk mendapatkan isolat bakteri endofit dari rumput teki (Cyperus rotundus) yang mampu melarutkan fosfat dan menghasilkan hormon AIA untuk mendukung pertumbuhan tanaman jagung. Sebanyak 15 isolat bakteri endofit dilakukan uji kemampuan melarutkan fosfat dan penghasil AIA.Isolat bakteri endofit AZ5, AZ12, AZ6 berkemampuan dalam melarutkan fosfat dengan memperoleh indeks kelarutan yaitu AZ5 10,27, AZ12 9,31 dan AZ6 5,75. Penghasil IAA tertinggi isolat AZ5 yaitu 49.91 μL/mL AZ12 48.18 μL/mL dan AZ6 44.45 μL/mL. Isolat bakteri endofit penghasil AIA tertinggi AZ5 mempunyai karakteristik morfologi koloni dengan bentuk circular; tepi entire; elevasi raised, warna putih kekuningan dan karakteristik morfologi sel adalah Gram positif, bentuk sel diplokokus. Karakteristik fisiologi dan biokimianya yaitu positif hidrolisis pati, positif hidrolisis gelatin, negatif pada media simon sitrat agar dan positif H2S. Tiga dari lima belas Isolat yang diuji untuk diaplikasikan terhadap pertumbuhan biji jagung, yaitu AZ5, AZ6, dan AZ12. Hasil aplikasi isolat bakteri endofit AZ5, AZ6, dan AZ12 pada tanaman jagung yang terbaik adalah perlakuan AZ5, kombinasi AZ5+AZ6 dan AZ5+AZ6+AZ12 terhadap semua parameter pengukuran tanaman.