x RINGKASAN
Lahan pasir besi memiliki kandungan bahan organik rendah dan memiliki kandungan besi (Fe) berkisar 38-59%, yang ditemukan di beberapa daerah pesisir Indonesia. Rendahnya kandungan bahan organik berpengaruh terhadap pertumbuhan tumbuhan dan organisme yang terdapat di lingkungan tersebut. Azospirillum adalah salah satu kelompok bakteri yang mampu tumbuh di lingkungan perakaran tumbuhan di tanah pasir besi.
Tujuan penelitian ini adalah untuk mengetahui karakteristik fisiologis isolat
Azospirillum spp. asal lahan pasir besi sebagai kandidat PGPR (Plant Growth Promoting Rhizobacteria), mengetahui efek pemberian isolat Azospirillum spp. asal lahan pasir besi terhadap perkecambahan biji tanaman jagung (Zea mays L.), dan mengetahui pengaruh inokulasi isolat Azospirillum spp. asal lahan pasir besi terhadap pertumbuhan vegetatif tanaman jagung. Penelitian dilakukan secara deskriptif untuk mengetahui karakter fisiologis Azospirillum spp. Penelitian secara eksperimental dengan Rancangan Acak Lengkap (RAL) dilakukan untuk mengetahui potensi isolat
Azospirillum spp. dalam meningkatkan perkecambahan dan pertumbuhan vegetatif tanaman jagung.
Hasil penelitian menunjukkan bahwa isolat Azospirillum spp. asal lahan pasir besi mampu melarutkan fosfat, memproduksi hormon tumbuh IAA, menghasilkan siderofor, dan menghasilkan ACC Deaminase, tetapi tidak bersifat antagonis terhadap beberapa fungi patogen. Isolat Azospirillum spp. asal lahan pasir besi berpengaruh terhadap persentase perkecambahan biji jagung terutama isolat Azospirillum sp. HR141 dengan persentase mencapai 100%. Inokulasi isolat Azospirillum spp. asal lahan pasir besi berpengaruh terhadap bobot basah dan kering tanaman jagung, namun tidak berpengaruh terhadap tinggi tanaman, panjang akar, dan kandungan klorofil daun. Isolat
Azospirillum spp. asal lahan pasir besi memiliki karakter fisologis sebagai kandidat PGPR.
Kata kunci : Azospirillum, jagung, PGPR.
xi SUMMARY
Iron sand lands have low organic matter content and it contains of iron (Fe) ranged from 38 to 59%, which is mostly found along the Indonesia coast. The low organic matter content of them affects on the growth of plants and organisms that occur in the environment. Azospirillum is one of bacterial group capable of growing in the plant rhizospheres on iron sand soil.
The purpose of this study was to know the physiological characteristics of
Azospirillum spp. isolated from iron sand soil as a candidate of PGPR (Plant Growth Promoting Rhizobacteria), to determine the effect of Azospirillum spp. isolated from iron sand soil on germination of maize (Zea mays L.) seeds, and to observe the effect of
Azospirillum spp. inoculation on vegetative growth of maize. To determine observation of physiological characteristics of Azospirillum spp. were carried out by descriptive methods. Method used to determine the potential of Azospirillum spp. isolates in improving vegetative growth of maize was Completely Randomized Design (CRD).
The results showed that isolates of Azospirillum spp. originated from iron sand soils capable of solubilizing phosphate, producing growth hormone IAA, producing siderophores, and producing ACC Deaminase, but they did not be able to inhibit the growth of pathogenic fungi. Inoculation of Azospirillum spp. isolates from iron sand soils effected maize seeds germination especially by isolate of Azospirillum sp. HR141 with 100% percentage. Inoculation of Azospirillum spp. isolates originated from iron sand soils affected the weight of wet and dry corn plants, but they did not effect on plant height, roots lenght, and chlorophyll content of leaves. Azospirillum spp. isolated from iron sand soils had physiological characters as candidates of PGPR.
Key words: Azospirillum, maize, PGPR.
