Effects of Indoleacetic Acid-Producingendophytic Fungi on Growth of Okra Seedling in Glyphosate-Contaminated Soil

Abstract

The effect of indoleacetic acid (IAA) produced by endophytic fungi, Bb6 andBb7, on okragrowth in 40 mmol/kg glyphosate contaminated soil was studied. The IAA concentrations produced by Bb6 and Bb7 were 1.40´10^-3 and 0.56´10^-3 M, respectively and these endophytic fungi were identified as Corynespora cassiicola and Colletotrichum gloeosporioides. There were 6 for seed induction; 1) imbibed with distilled water and irrigated with tap water (T1) 2) imbibed with fungal medium and irrigated with tap water (T2) 3) imbibed with distilled water and watered once with fungal medium after germination (T3) 4) imbibed and  watered once with fungal medium after germination (T4)  5) imbibed with containing tryptophan 2 mg/ml (PDB+T) and irrigated with tap water (T5) 6) imbibed with distilled water and watered once with PDB+T after germination (T6). Seeds from each induction were sown in both soils for 13 days. In glyphosate-contaminated soil, C. cassiicola medium did not affect plant growth but chlorophyll a contents were not different in T2, T4 and T5 when compared with non-contaminated soil and seedling from T2 and T4 increased chlorophyll a and b contents in leaves. For                                C. gloeosporioides, all methods did not enhance any growth of okra seedling. Seed induction with C. cassiicola medium could protect chlorophyll a content in glyphosate-contaminated soil.