Record ID No. |
659 |
Author(s) |
Van Auken, OW; Freidrich, R. , 2006 |
Affiliation |
Univ Texas, Dept Biol, San Antonio, TX 78249 |
Title |
Growth and mycorrhizal infection of two annual sunflowers with added nutrients, fungicide or salts |
Source. Vol.(no):Page |
Texas Journal of Science. 58(3):195-218p. |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Biocides |
Sub-subjects |
Fungicides |
Host |
Helianthus paradoxus, H. annuus |
Organism |
AMF |
Country |
U.S.A., North America |
Abstracts |
Helianthus paradoxus and H. annuus, two annual sunflowers, form symbiosis with arbuscular mycorrhizal fungi (AMF). This relationship and its influence on the growth and dry mass of the two sunflowers was examined. Time of growth, nutrient status, reduction of mycorrhizal fungi, and soil salinity were the experimental treatments. Their effects on the infection of the roots and the above and belowground dry mass of both species were the response variables. Plants were grown in a native Patrick series Mollisol and the plants were colonized by native AMF. Helianthus annuus and H. paradoxus mycorrhizal infection was relatively stable at 49.7 +/- 1.9% over ten weeks. When nutrients were increased in a separate experiment, the mean percent mycorrhizal infection of both species dropped from 51.0 +/- 1.4% to 33.3 +/- 0.7%, but dry mass increased. Total dry mass of H. annuus increased 12.3 times to 18.35 +/- 2.61 g/pot and for H. paradoxus it increased 3.1 times to 4.15 +/- 0.51 g/pot compared to no added nutrients. Reducing or eliminating the mycorrhizal fungi from the soil with heat sterilization or fungicide did not have a significant deleterious effect on growth in either species. Both species appear to be facultative mycotrophs. At increased levels of soil salinity, H. paradoxus mean percent mycorrhizal infection increased, but the infection in H. annuus decreased. Helianthus paradoxus showed greater survivorship at the highest levels of salinity. However, above and belowground dry mass of both species decreased with increased soil salinity. |