Effects of seed phosphorus concentration on the emergence and growth of subterranean clover (Trifolium subterraneum)

Abstract

Subterranean clover seed (Trifolium subterraneum cv. Dalkeith) with phosphorus concentrations of 0.75% (high P seed) and 0.48% (low P seed) and of uniform size (2.0-2.4 mm diameter) was used to measure the effect of seed P concentrations on seedling emergence and growth.Seedling emergence numbers were 35% greater for the high P seed, and this effect was independent of external P supply. High P seed also emerged more quickly than low P seed.Leaf emergence was faster and shoot dry weight was greater for seedlings grown from high compared with low P seed, but only when external P supply was deficient for plant growth. Phosphorus concentrations in the shoots of two-week old seedlings were 32-51% higher for high P seed, although by four weeks plants grown from high and low P seed had similar concentrations of P in their shoots. We suggest that establishing pastures using high P seed would improve both early and late season pasture production.

Seed P-enrichment as an effective P supply to wheat

“…The Pi concentrations in soil solutions are usually very low (typically less than 1 μM) because most Pi is heavily bonded with the relatively abundant cations aluminum (Al), calcium (Ca), and iron (Fe) (Raghothama and Karthikeyan 2005). Although fertilizer P application can temporarily increase the Pi concentration in soil solution, it is immobilized almost immediately due to sorption of P by soil (Stevenson and Cole 1999). Soil interference only allows plants to acquire P within a few millimetres of root surfaces, and acquisition is determined by the volume of soil explored by plant roots, which is normally less than 1% and rarely reaches 5% (Barber 1995).…”

“…Soil interference only allows plants to acquire P within a few millimetres of root surfaces, and acquisition is determined by the volume of soil explored by plant roots, which is normally less than 1% and rarely reaches 5% (Barber 1995). As a result, most fertilizer P, often more than 90%, is not taken up by plants with the remainder being retained by soil in sparingly soluble forms (Stevenson and Cole 1999). Hence there is the need to develop systems to improve use of soil and fertilizer P for crop production.…”

Reproductive response to nitrogen and phosphorus fertilization along the Hawaiian archipelago’s natural soil fertility gradient

“…Nutrients allocated to seeds will serve as food reserves within the seeds, powering the metabolic processes essential to the growth and development of the seedling (Bewley and Black 1985). Enhanced P concentration in seeds has been shown to improve germination rate and percentage, growth rate, and competitive ability (Parrish and Bazzaz 1985;Thomson and Bolger 1993;Sills and Nienhuis 1995), increase root growth (Milberg et al 1998), and allow for greater P-uptake capabilities (Shane et al 2008;Groom and Lamont 2010). P storage in seeds has been identified as an important adaptive strategy in Proteaceae, a family prominently growing on P-limited soils.…”

“…Furthermore, a seedling's ability to capture P from the soil can also be improved by having a large storage of P within the seed Fertilization treatment effect on percent change (i.e., relative difference from the control) in N and P input from a inflorescences and b seeds (Shane and Lambers 2006;Shane et al 2008;Groom and Lamont 2010). A possible mechanism for this greater P uptake was demonstrated by Thomson and Bolger (1993) using seeds of Trifolium subterranean grown in soils of varying P levels. The authors found that a greater P reserve increased emergence rate, percentage seedling emergence, and rate of leaf emergence.…”

“…The authors found that a greater P reserve increased emergence rate, percentage seedling emergence, and rate of leaf emergence. Therefore, the seeds with more P reserve were provided with a competitive advantage because they not only emerged from the soil faster but developed photosynthesizing leaves sooner, which would feedback to faster growth rates (Thomson and Bolger 1993). Increased early root growth that assists in uptake of P by seedlings has also been suggested as a benefit of seeds with larger nutrient reserves (Milberg et al 1998).…”