PHOSPHATE SOLUBILIZATION POTENTIAL AND PHOSPHATASE ACTIVITY OF RHIZOSPHERIC TRICHODERMA SPP.

Ano: 2010 | Volume: 41 | Número: 3

Autores: Anil Kapri, Lakshmi Tewari

Palavras-chave: Phosphate solubilization, Trichoderma, Acid phosphatase, Alkaline phosphatase, Chickpea

Resumo Inglês:

Trichoderma sp., a well known biological control agent against several phytopathogens, was tested for its
phosphate (P) solubilizing potential. Fourteen strains of Trichoderma sp. were isolated from the forest tree
rhizospheres of pinus, deodar, bamboo, guava and oak on Trichoderma selective medium. The isolates
were tested for their in-vitro P-solubilizing potential using National Botanical Research Institute Phosphate
(NBRIP) broth containing tricalcium phosphate (TCP) as the sole P source, and compared with a standard
culture of T. harzianum. All the cultures were found to solubilize TCP but with varying potential. The
isolate DRT-1 showed maximum amount of soluble phosphate (404.07 μg.ml-1), followed by the standard
culture of T. harzianum (386.42 μg.ml-1) after 96 h of incubation at 30+10C. Extra-cellular acid and
alkaline phosphatases of the fungus were induced only in the presence of insoluble phosphorus source
(TCP). High extra-cellular alkaline phosphatase activity was recorded for the isolate DRT-1 (14.50 U.ml-1)
followed by the standard culture (13.41 U.ml-1) at 72h. The cultures showed much lesser acid phosphatase
activities. Under glasshouse conditions, Trichoderma sp. inoculation increased chickpea (Cicer arietinum)
growth parameters including shoot length, root length, fresh and dry weight of shoot as well as roots, in Pdeficient
soil containing only bound phosphate (TCP). Shoot weight was increased by 23% and 33% by
inoculation with the isolate DRT-1 in the soil amended with 100 and 200 mg TCP kg-1 soil, respectively,
after 60 d of sowing. The study explores high P-solubilizing potential of Trichoderma sp., which can be
exploited for the solubilization of fixed phosphates present in the soil, thereby enhancing soil fertility and
plant growth.