VA-mycorrhiza mediated P effect on growth and yield of sunflower (Helianthus annuus L.) at different P levels

Abstract

A field trial was conducted to study the response of sunflower (Helianthus annuus L.) to different phosphorus levels (16, 24 or 32 kg P ha -1) and inoculation with vesicular-arbuscular mycorrhizal fungus, Glomus fasciculatum on vertisol during summer 1993. At the vegetative stage of sunflower, percent mycorrhizal root colonization, spore count, dry biomass and P uptake did not differ significantly between inoculated and uninoculated control plants. However, at later stages (flowering and maturity) percent root colonization, spore count, total dry biomass and total P uptake were significantly higher in inoculated plants than in uninoculated control plants. The total dry biomass, P content and seed yield increased with increasing P level in uninoculated plants, whereas no significant difference was observed between 16 and 32 kg P ha -1 in inoculated plants. The positive effect of mycorrhizal inoculation decreased with increasing P level above 16 kg P ha -l, due to decreased percent root colonization and spore count at higher P levels.

Mycorrhizal Fungi Increase Chromium Uptake by Sunflower Plants: Influence on Tissue Mineral Concentration, Growth, and Gas Exchange

“…Mycorrhiza can increase P uptake by sunflower. [20] In a non-mycorrhizal study of Cr in tomato plants, there was a nonsignificant trend of decreased leaf P at higher Cr levels. [42] This is one of the first reports of Cr reducing plant g s and A. Chromium is thought to alter plant membrane systems, but the physiological and metabolic responses are not well understood.…”

“…[14][15][16][17][18][19] An important arbuscular mycorrhizal genus is Glomus, which colonize a variety of host species, [6] including sunflower. [20] Mycorrhizal fungi are a direct link between soil and roots, and consequently of great importance in phytoremediation-potentially enhancing heavy metal availability and plant tolerance. Little is known of the ability of mycorrhizal fungi to enhance plant tolerance or phytoaccumulation of Cr.…”

Inoculation of field-established mulberry and papaya with arbuscular mycorrhizal fungi and a mycorrhiza helper bacterium

“…Iqbal and Qureshi (1972) reported 85% increase in height of sunflower plants inoculated with AM fungi compared with uninoculated controls under field conditions. Similarly, AM fungal inoculation in the nursery or at the time of planting resulting in improved plant height and growth under field conditions has been reported in crops such as maize (Powell and Bagyaraj 1984), mulberry (Katiyar et al 1995), finger millet (Govinda Rao et al 1993) and sunflower (Chandrashekara et al 1995).…”

“…It has been pointed out that AM inoculation could have a large economic impact on agriculture and horticulture if the beneficial effects of AM fungi observed under pot culture studies could be emulated under field conditions. Though benefits of AM fungi under field conditions have been reported for annuals and perennials inoculated in the nursery (Bagyaraj 1984;Chandrashekara et al 1995), there is practically no information on the response of perennial crops already established in the field to inoculation with AM fungi. Hence, the present study examined the response of 10-year-old mulberry plants grown under rain-fed conditions in a garden, and 1.5-year-old papaya trees grown under drip irrigation under field conditions to AM inoculation either alone or together with a mycorrhiza helper bacterium (MHB) at two different levels of P fertilizer.…”

Agronomic Management of Indigenous Mycorrhizas

“…Fertilizer application, particularly P fertilizer and the associated increase in soil P level, decreases AM fungal infectivity and effectiveness (Dickson et al 1999, Kahiluoto et al 2000, Sorensen et al 2005) and spore density (Chandrashekara et al 1995). Irrespective of high levels of P in the soil, it is the concentration of P in the root system that determines whether AM fungi colonize roots (Menge et al 1978).…”