Stability of the Inherent Target Metallome in Seed Crops and a Mushroom Grown on Soils of Extreme Mineral Spans

Abstract

Extremes in soil mineral supply alter the metallome of seeds much less than that of their herbage. The underlying mechanisms of mineral homeostasis and the "puzzle of seed filling" are not yet understood. Field crops of wheat, rye, pea, and the mushroom Kuehneromyces mutabilis were established on a set of metalliferous uranium mine soils and alluvial sands. Mineral concentrations in mature plants were determined from roots to seeds (and to fungal basidiospores) by ICP-MS following microwave digestion. The results referred to the concentrations of soil minerals to illustrate regulatory breaks in their flow across the plant sections. Root mineral concentrations fell to a mean of 7.8% in the lower stem of wheat in proportions deviating from those in seeds. Following down-and up-regulations in the flow, the rachis/seed interface configured with cuts in the range of 1.6%-12% (AsPbUZn) and up-regulations in the range of 106%-728% (CuMgMnP) the final grain metallome. Those of pea seeds and basidiospores were controlled accordingly. Soil concentration spans of 9-109ˆin CuFeMnNiZn shrank thereby to 1.3-2ˆin seeds to reveal the plateau of the cultivar's desired target metallome. This was brought about by adaptations of the seed:soil transfer factors which increased proportionally in lower-concentrated soils. The plants thereby distinguished chemically similar elements (As/P; Cd/Zn) and incorporated even non-essential ones actively. It is presumed that high-and low-concentrated soils may impair the mineral concentrations of phloems as the donors of seed minerals. In an analytical and strategic top performance, essential and non-essential phloem constituents are identified and individually transferred to the propagules in precisely delimited quantities.

Basidiospores from Wood-Decay Fungi Transform Laccase Substrates in the Absence of Glucose and Nitrogen Supplements

“…Table 3 presents the outregulated metal load of wheat grains as the only available landmark for tolerable concentration spans which ensures, e.g., the adequate supply of the germinating seedling by avoiding metal stress [55,56]. Unwashed spores of Kmt as organisms adapted to the same geochemical environment were moderately higher in Co, Fe, K, Mn, Na and Ni but not in the other minerals.…”

Gradual Accumulation of Heavy Metals in an Industrial Wheat Crop from Uranium Mine Soil and the Potential Use of the Herbage

“…Severe incisions into the flow of all the minerals except K occurred at the root/lower stem interface (Table 3; Figure 1a). The concentrations predominantly rising in the upper shoot were once more dramatically down-or up-regulated at the extremely versatile rachis/grain interface in more or less successful attempts to realize the inherent seed target metallome of the cultivar [19][20][21]72]. Unlike the herbage, grains respond least to changes in agronomic conditions and the supply with soil minerals [83][84][85] and nitrogen [18,23], and they stabilize their metallome inherently in a narrow range [21,23,27].…”

“…Fixing soil A percentages at factor 1, the soil uptake rates of Ca, Cd, K, and P by soil C-grown tissues coincided with those from soil A ( Figure 5). Unlike Cu and Cr, Mg and most of the traces were taken up at drastically lower rates from the resources in soil C. Attempts to level the Cu and Mg content of soil A-and soil C-grown grains during seed fill in the inherently narrow span (Table 1; [27,72]) may have caused the relatively elevated and reduced respective uptake of these elements, whereas variations in the uptake rates of other elements, for example, by mechanisms of uptake competition, shall not be derived from the data. The respective conclusions for a single organism should solely be drawn from lab-scale tests on defined media rather than on polymetallic soils.…”

“…Cadmium concentrations in the herbage violated the hygiene standards of forage (1 mg·kg −1 ; [5]), whereas the high Zn load may be tolerable for monogastric livestock (500-1000 mg·kg −1 ) rather than for ruminants (300-500 mg·kg −1 ; [71]). The strict indigenous HM control of seeds [19,20,28,72] at least held the grains obtained from a soil of 40 mg·kg −1 Cd to the permissible range of forage ( Table 1). The roots, herbage, and seeds grown on the non-contaminated soil C persisted in the range of 'normal plant HM concentrations' (Table 1; [62,65]) and yielded food quality grains.…”

“…It is part of the plant's strategic and analytical top performance to identify the individual organic and mineral phloem constituents and to translocate them in delimited quantities to the grain in realizing its genetically pre-determined composition [72]. The cytoplasm strands in sieve tubes actively capture the single phloem constituents in congruence with the current plant metabolic state [90].…”