The effects of phosphorus and form of nitrogen supply on leaf cell size and nutrient content in Trifolium repens and Lotus uliginosus

Abstract

White clover (Grasslands Huia) and lotus (Grasslands Maku) were grown in pots of soil at a range of phosphorus supply, and reliant on symbiotic nitrogen fixation (SN plants) or entirely on mineral nitrogen {MN plants). Shoots increased in weight with phosphorus supply. White clover MN shoots were bigger than those of SN plants except at the lowest level of phosphorus supply; lotus MN shoots were only bigger than SN shoots at the highest level of phosphorus supply. Leaf growth rate and size increased with phosphorus supply but were not significantly affected by the nitrogen treatments.Estimates of cell size were made by determining DNA concentration, by digestion of tissue followed by counting and by taking vinyl impressions of epidermal cell surfaces. Lotus cells are bigger than those of white clover. "Digested' cell sizes were not significantly afTected by changes in phosphorus supply. Epidermal cell size increased with phosphorus supply, but the relationship was weaker in SN than in MN plants. Methods which give values for 'average' cell size are capable of detecting large-scale diiTerences. but methods able to resolve cell heterogeneity are necessary for an accurate picture of the relationship between leaf growth and cellular nutrition.Average concentrations of total and inorganic phosphorus on a DNA basis did not differ between the species, contrary to concentrations on a dry weight basis, indicating that differences in phosphorus efficiency can be partly explained on

Soil Application of Sewage Sludge Treated with Clay Minerals or Biochar and Its Effect on Soil Properties and White Clover’s (Trifolium repens L.) Growth and Arbuscular Mycorrhizal Fungal Root Colonization

“…The concentrations of macronutrients in the aboveground biomass of the plants grown in acid soil treatments ranged between 19.9 and 43.8, 2.2 and 3.7, 5.6 and 42.9, 6.4 and 30.5 and 2.0 and 3.3 g kg −1 for N, P, K, Ca and Mg, respectively. Comparing these concentrations with those reported in the literature [19,47], it was evidenced that plant N, P, K and Mg contents were within the common range in all cases, whereas the Ca content was low in all cases, except for the limed sludge treatment (AcL).…”

“…According to root biomass yields, treatments followed the order AlB > AlBc > AlD > AlL > AlIF > AlC > AlV > AIFX. The nitrogen, P, K, Ca and Mg contents of white clover plants grown in alkaline soil treatments were within the common range [19,47] and the respective concentrations were 26.6-42.8, 1.7-2.2, 27.6-37.7, 14.3-42.1 and 3.2-5.2 g kg −1 . Plant uptake of macronutrients followed the same pattern as biomass yield and the poor effect of treatments with limed and vermiculite-treated sludge (AlL, AlV) on white clover yield was accompanied by reduced N, P and K uptake (Figure 2b).…”

“…It was observed that Zn uptake was depressed in the treatment with the biochar-treated sludge (AcBc) (Figure 3a); although no effect of the particular treatment on soil-available Zn was observed. Concentrations of Cu, Zn, Fe, Mn and B in white clover plants grown in acid soil treatments were either within usual ranges or excessive [19,47] and ranged between 11.3 and 42.4, 18.5 Soil pH increments promoted the availability and, consequently, the plant uptake of Cu, Zn and B in the acid soil treatments with bentonite-or vermiculite-treated or untreated sludge, compared to the control and also to the inorganic fertilization treatments (Figure 3a). Conversely, plant uptake of almost all micronutrients after the treatment with the limed sludge (AcL) was similar to or lower than the control, probably because of the strongly alkaline reaction of the specific treatment.…”

“…Increasing cultivation and productivity of white clover through soil application of sewage sludge is in accordance with the European Green Deal since inorganic N fertilization in arable soils can be reduced by both sewage sludge's N content and white clover's atmospheric N 2 fixation [17]. The response of white clover to liming and inorganic fertilization has also been investigated so far [18][19][20]. Clover has also been used as an indicator plant for investigating the effects of soil-applied sewage sludge [15].…”

Ecological correlates of body size in relation to cell size and cell number: patterns in flies, fish, fruits and foliage

“…Comparisons of different populations of plants and vertebrates across environmental gradients are clearly needed. Roggatz et al (1999); (2) Trapani et al (1999); (3) Walter et al (2003); (4) Cruz et al (1997); (5) Hart & Collier (1994); (6) Milligan & Dale (1988); (7) Milthorpe & Newton (1963); (8) Isanogle (1944); (9) Butler (1963); (10) Wilson (1966); (11) Dengler (1980); (12) Granier and Tardieu (1999); (13) Granier et al (2000); (14) Slade (1970); (15) Friend & Pomeroy (1970); (16) Rahim & Fordham (1991) (17) Schoch (1972); (18) Paul (1984); (19) Hoek et al (1993); (20) Auld et al (1978) Fourth, can differences in cellular mechanisms explain differences in growth trajectories (crossing versus nested)? The best data exist for D. melanogaster: nested trajectories tend to be associated with differences in cell number while crossing trajectories more often are associated with cell size.…”