
TY  - JOUR
A1  - Olsen, J. K. 
A1  - Schaefer, J. T. 
A1  - Edwards, D. G. 
A1  - Hunter, M. N. 
A1  - Galea, V. J. 
A1  - Muller, L. M. 
T1  - Effects of mycorrhizae, established from an existing intact hyphal network, on the growth response of capsicum (<emph type="2">Capsicum annuum</emph> L.) and tomato (<emph type="2">Lycopersicon esculentum</emph> Mill.) to five rates of applied phosphorus
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 1999
VL  - 50
IS  - 2
SP  - 223
EP  - 238
KW  - 
UR  - https://doi.org/10.1071/A97167 
N2  - The growth response of 2 vegetable crops to 5 rates of applied phosphorus (P)in the presence or absence of an existing network of extraradical mycorrhizalmycelium was determined in 2 greenhouse pot experiments (Expt 1, autumnwinter; Expt 2, summer autumn) using a low-P growth medium (6 or 5 mgNaHCO3-extractable P/kg for Expt 1 or 2,respectively). In both experiments, capsicum(Capsicum annuum L.) and tomato(Lycopersicon esculentum Mill.) plants were grown at 0(P1 ), 9.2 (P2), 27.5(P3 ), 82.5 (P4 ), or 248(P5) mg P/kg oven-dry soil (spot-placed at sowing)within a nylon mesh (pore size 44 &#181;m). The mesh excluded roots from theoriginal sunflower (Helianthus annuus L.) host plants,to which either live (VAM+) or killed (VAM&#8211;) mycorrhizal&#91;Glomus etunicatum Becker &#38; Gerdemann andGlomus mosseae (Nicol. &#38; Gerd.) Gerdemann &#38; Trappe&#93; inoculum was added at sowing. The mesh did allow fungal hyphae togrow into the growth medium contained by the mesh.Whereas VAM+ plants generally had higher P concentrations in indextissues than VAM&#8211; plants at low P rates, a concomitant increase in drymatter yield was restricted to the P1 rate. AtP1 in Expt 2, the increase in the dry weight of wholeplants as a result of VAM colonisation was as large as 91.7-fold and 17.9-foldfor capsicum and tomato, respectively. Root starch analysis indicated that thelower dry matter yields of VAM+ plants than of VAM&#8211; plants at&#x2265;P2 could be attributed to insufficient photosynthateproduction by VAM+ plants to meet the carbon (C) demand of both host andendophytes within the relatively low-light environment of the greenhouse(average daily solar irradiance of 8.4 MJ/m2 forExpt 1 and 13.4 MJ/m2 for Expt 2).The growth response of vegetable crops grown within the greenhouse fromcolonisation by an established mycorrhizal mycelium appears to depend on acritical balance of P and C supply; i.e. at P1, P wasmore limiting than C, and the increased uptake of P as a result ofcolonisation of plant roots by VAM resulted in a growth response. At higher Prates, C was more limiting than P due to low light in the greenhouse, and theadditional demand for photosynthate imposed by the endophytes on the hostresulted in a growth depression relative to non-mycorrhizal plants. 
ER  -

