The Potential of Forest Litter Penicillium and Trichoderma on IAA Production in Meranti Leaves Compost

Abstract

Environmental manipulation through utilization of forest litter combined with microbial inhabiting rhizosphere is applied to achieve sustainable, prospective and healthy meranti (Shorea spp.) forest. Penicillium IPBCC 09 622 (SI1) and Trichoderma IPBCC 09 620 (SI2) originated from Dipterocarp litter were known to be able to reduce C/N ratio of Dipterocarp litter as well as produce IAA (Indole-3-Acetic Acid) in vitro. This study is aiming to assess the potential of these two fungi as a single (SI1, SI2) or their consortium (SI3) inoculants in producing IAA in meranti leaves compost. The compost was consisted of a mixture of meranti leave litter (83%), rice bran (15%) and urea (2%) at 60% moisture content. About 100 g of this mixture were placed in each polybag and steamed at 104oC for 30 minutes. The mixture were then inoculated with fungal biomass (SI1, SI2, or SI3) and then kept for 4 months. Uninoculated compost (SI-), steamed compost containing 4 ppm IAA synthetic (SA), and unsteamed and uninoculated compost (S-I-) were used as control. Each treatment had 3 replications. Observation was done monthly on population of Penicillium and Trichoderma, C/N ratio, water content (WC), organoleptic (color, texture and smell) and temperature (t) of the compost. At the end of decomposting period, minerals P, K, Ca and Mg, weight loss, decomposition rate analyses and bio-assay using shoot cutting of meranti tembaga (Shorea leprosula) were done. Observation indicated that Penicillium did not survive, but Trichoderma survived throughtout decomposition period. Penicillium did not have lignases, while Trichoderma only had tyrosinase. Fungal contamination occured during composting periods in all compost. About 10 fungal species were isolated in which Trichoderma was dominant. This contamination might effect to the overall research result. C/N ratio, WC and t content fluctuated between 15.93-45.47, 12.88-67.31% and 26-30.33oC respectively. At the end of composting period, C/N ratio was 15.93-18.53, WC was 26.55-50.94%, t was 29.67-30.33oC and minerals (P, K, Ca and Mg) content were 0.27-0.39%, 0.32-2.58%, 0.67-1.34%, 0.26-0.94%, respectively. Weight loss and decomposition rates was low, approximately 2.33-10.67% and 0.0058-0.028/yr respectively. The color, texture and smell of the compost did not meet the criteria SNI no. 19-7030-2004, while the C/N ratio and WC met SNI criteria. IAA production more were higher if the compost were inoculated with Trichoderma or it was infested by Trichoderma. IAA varied betwen 0.17-10.91 ppm depending on treatments. IAA detected using HPLC (high performance liquid chromatography) was slightly lower than those obtained from Salkowsky reagent. At the end of the composting, the compost was mixed with sterilized soil (1:1) and used for planting media of stem cutting. Bio-assay indicated that only 0.00-13.33% shoot cuttings of meranti tembaga showed root initiation depending on the composts. In conclusion Penicillium was not a potential agent, but Trichoderma was potential for IAA production in meranti leaves litter compost.

Pemanfaatan serasah hutan dan mikrobanya menjadi salah satu program pemerintah menuju hutan meranti yang sehat, prospektif dan lestari. Penicillium IPBCC 09.622 (SI1) dan Trichoderma IPBCC 09.620 (SI2) asal serasah hutan Dipterokarp telah dilaporkan berpotensi sebagai dekomposer sekaligus penghasil AIA (Asam Indol Asetat) secara in vitro. Penelitian ini bertujuan untuk mengkaji potensi dua kapang tersebut secara tunggal (SI1, SI2) atau konsorsium (SI3) dalam mendekomposisi serasah meranti sekaligus menghasilkan AIA pada kompos meranti. Penelitian ini meliputi pengomposan serasah meranti selama empat bulan, produksi AIA selama proses pengomposan dan pengujian kompos meranti terhadap inisiasi akar stek meranti. Bahan kompos terdiri atas campuran serasah meranti (83%), dedak (15%) dan urea (2%) pada kadar air 60%. Sekitar 100 g bahan kompos dimasukkan dalam setiap baglog, baglog disterilisasi menggunakan mesin panas uap (steam) pada suhu 104oC selama 30 menit. Bahan kompos diinokulasi biomasa kapang (SI1, SI2, atau SI3), selanjutnya diinkubasi selama empat bulan. Kompos tanpa inokulan (SI-), kompos disteam dengan 4 ppm AIA sintetik (SA) dan kompos tanpa disteam dan tanpa inokulan (S-I-) digunakan sebagai pembanding. Pengamatan dilakukan setiap bulan selama empat bulan pengomposan terhadap populasi Penicillium dan Trichoderma, rasio C/N, kadar air (KA), suhu, organoleptik kompos (warna, tekstur dan bau) serta kadar AIA. Kandungan hara makro (P, K, Ca dan Mg), kehilangan bobot kompos dan laju dekomposisi diamati pada akhir pengomposan. Selanjutnya kompos yang diperoleh diuji pengaruhnya terhadap inisiasi akar stek meranti.