Evaluation of the fungal endophyte Clonostachys rosea as an inoculant to enhance growth, fitness and productivity of crop plants.

摘要

C. rosea strain 88-710 was evaluated for its ability to promote growth and productivity of miniature roses (Rosa hybrida cv. Bianca), geraniums (Pelargonium hortorum cv. Schone Helena) and cucumber (cv. Loustik) grown in the absence or near absence of pathogens. For comparison, Pseudomonas chlororaphis strain 63-28 was also evaluated in cucumbers. For the treatment of roses, conidial suspensions (5x106 conidia ml-1 of water) of C. rosea were applied at the cuttings stage, or after the first or second trimming of the foliage, or in combinations of these. Compared with the controls, the endophyte accelerated the rooting of cuttings, reduced root dieback following foliar trimming by more than 70%, maintained rapid shoot growth, and reduced the number of senescent and dead leaves by 55-80%. The flowers of treated plants developed earlier and more vigorously than the control, and the plants were shipping-ready 7-14 days earlier. Treatment of geranium cuttings by immersion in 5 x106 conidia ml-1 increased root production by 3-fold and plant survival by 27%. In cucumber grown in hydroponics in a greenhouse, the incorporation of C. rosea into the nutrient solution at a final density of 1x105 conidia ml-1 increased the leaf area by 28% after 16 days, and root dry mass by 40% after 19 days; the corresponding values for P. chlororaphis applied at 1x105 CFU [colony-forming units] ml-1 were 39 and 48%. Neither organism influenced the net CO2 assimilation rate or chlorophyll fluorescence per unit leaf area. In a related experiment, C. rosea and P. chlororaphis increased plant height by 48-66% and 60-71%, and root dry mass by 27-30 and 28-36%, respectively. In a commercial greenhouse, the respective microbes increased the number of marketable cucumber fruits by 11.1 and 10.5%. Th results indicated that C. rosea strain 88-710 and P. chlororaphis 63-28 have potential for use as inoculants to enhance crop performance.