Penapisan Bakteri Pemacu Tumbuh asal Rizosfer Tanaman Lada

Abstract

Plant Growth Promoting Rhizobacteria (PGPR) adalah kelompok bakteri rizosfer yang dapat memacu pertumbuhan tanaman. PGPR memiliki peran dalam pertumbuhan tanaman sebagai penghasil indole acetic acid (IAA), penambat nitrogen, dan pelarut fosfat. Penelitian ini bertujuan menganalisa kemampuan bakteri asal rizosfer tanaman lada sebagai pemacu tumbuh dengan menguji kemampuan bakteri dalam memproduksi IAA, menambat nitrogen, dan melarutkan fosfat. Sebanyak 21 isolat bakteri rizosfer asal tanaman lada dapat menghasilkan IAA dengan konsentrasi tertinggi 143,34 mg/L dihasilkan oleh isolat RB7, dan konsentrasi terendah 3,65 mg/L dihasilkan oleh isolat GK2B11. Uji pemacuan tumbuh kecambah jagung menunjukkan bahwa, 3 isolat (BM3A5, RA8, RB7) mampu meningkatkan panjang radikula, panjang hipokotil, jumlah akar lateral, berat basah, dan berat kering kecambah jagung secara signifikan. Sebanyak 8 dari 21 isolat dapat menambat nitrogen. Sebanyak 8 dari 21 isolat dapat melarutkan fosfat dengan indeks tertinggi 3,40 dihasilkan oleh isolat KL3A6. Isolat bakteri asal rizosfer tanaman lada yang memiliki potensi terbaik sebagai PGPR yaitu RB7 karena mampu menghasilkan IAA, menambat nitrogen, melarutkan fosfat, dan memacu pertumbuhan tanaman.

Plant Growth Promoting Rhizobacteria (PGPR) are a group of rhizosphere bacteria that can promote plant growth. PGPR play a role in plant growth as producers of indole acetic acid (IAA), nitrogen fixers, and phosphate solubilizers. This study aims to analyse the potential of rhizosphere bacteria from pepper plants as growth promoters by testing the bacteria's ability to produce IAA, fix nitrogen, and solubilize phosphate. A total of 21 rhizosphere bacterial isolates from pepper plants were able to produce IAA, with the highest concentration of 143.34 mg/L produced by isolate RB7, and the lowest concentration of 3.65 mg/L produced by isolate GK2B11. The growth promotion test on corn seedlings showed that 3 isolates (BM3A5, RA8, RB7) significantly increased the length of the radicle, hypocotyl, number of lateral roots, fresh weight, and dry weight of corn seedlings. Eight of the 21 isolates were able to fix nitrogen. Eight of the 21 isolates were able to solubilize phosphate, with the highest solubilization index of 3.40 produced by isolate KL3A6. The rhizosphere bacterial isolate from pepper plants with the best potential as a PGPR is RB7, as it has the ability to produce IAA, fix nitrogen, solubilize phosphate, and enhance plant growth.