Responses to Low P-Supply in Breeding Lines of White Clover (Trifolium Repens L.) Reveals Two Tiers of Responses

Abstract

2 Four breeding lines (BLs) of white clover, which range in terms of their disposition to increase biomass in response to low or high phosphate (P) levels in soil, were evaluated further when grown hydroponically. BL 45 increased both fresh and dry weight in response to P-deprivation, while BL 49 displayed the same significant stimulation in response to sufficient P. However, when compared these lines did not accumulate any significantly higher levels of P, and all four lines showed the same changes to root:shoot ratio in response to P-deprivation, as well as the induction of both soluble and cell-wall-associated acid phosphatase activity. These results confirm that there is no direct relationship between growth (as an increase in biomass) and acid phosphatase activity and further some responses to P-deprivation may be common to all genetic backgrounds suggesting that they are not part of the intricate mechanisms governing these responses.

Respuesta de accesiones naturalizadas de trébol blanco a la condición limitante de fósforo en un Andisol

“…Soil P deficiency is considered the main limitation for white clover's growth and development (Lloyd et al, 2014;Woodfield and Caradus, 1996). It has been demonstrated that these species can generate adaptation mechanisms to face low P in soil (Caradus and Snaydon, 1986;Effendy et al, 2014). These adaptations may be morphological; such as greater length and root surface to increase the uptake of P from the soil (Caradus, 1981), or physiological; through an increase of the efficiency of use of the internal P for the production of biomass aerial and root (Haling et al, 2016).…”

“…These adaptations may be morphological; such as greater length and root surface to increase the uptake of P from the soil (Caradus, 1981), or physiological; through an increase of the efficiency of use of the internal P for the production of biomass aerial and root (Haling et al, 2016). These adaptation mechanisms are naturally generated in white clover populations growing in a native or naturalized manner under low P (Caradus and Dunn, 2000) and express themselves differently in response to the level of P deficiency in soils (Caradus and Snaydon, 1986;Effendy et al, 2014). They are thus evaluated as phosphorus use efficiency (PUE) (Gourley et al, 1993).…”

“…Differences in P responses of a naturalized population of white clover have been reported under field and glasshouse conditions (Blair and Godwin, 1991;Effendy et al, 2014;Godwin and Blair, 1991;Trolove et al, 1996). It has also been reported that the evaluation of these species under glasshouse conditions may not be related to the P response under field conditions (Richardson et al, 2011).…”

“…However, species such as white clover, are characterized by low efficiency of use of P with respect to grasses (Woodfield and Caradus, 1996). However, the phenotypic plasticity of species such as white clover, give the possibility of selecting native populations adapted to limiting conditions of P (Effendy et al, 2014;Lloyd et al, 2014;Simpson et al, 2014).…”