Trace element deficiency or toxicity dependent on plant genotype

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Abstract
Genetic adaptation of plants to innate environmental conditions has made them functionally diverse, and to predict how they will respond to a new environment is difficult. For example, cotton and lettuce were chlorotic when grown under low‐pressure sodium (LPS) but not chlorotic when grown under cool‐white fluorescent (CWF) lamps. Petunia was green under both type lamps. Chlorophyll synthesis in cotton and lettuce grown with CWF lamps was related to reduction of Fe3+ to Fe2+ in solutions. Plant species and cultivars differed in their response to Fe, Cu, Zn, Mn, B, and Mo deficiency stresses and in their tolerance to relatively high concentrations of either Mn or Al when grown in soils or in nutrient solutions. For example, Bragg soybean was Mn‐intolerant, Lee soybean was Mn‐tolerant and their progeny (B x L, L x B) varied in Mn‐tolerance when grown in a Mn‐toxic soil and in nutrient solutions containing 6.5 mg Mn/1. All plants contained about 500 mg Mn/μg dry matter top. Less Fe was absorbed and transported by each progeny than by parent Bragg, and more Fe was absorbed and transported by each progeny than by the parent Lee. Bragg was less tolerant and Lee more tolerant to Mn than either of their progeny (B x L or L x B). Genetic factors associated with Fe absorption and transport seemed to be associated with tolerance of these soybeans to Mn and may involve the ionic form of Mn (manganous or manganic) in the plant. Trace element chemistry reaches into all phases of biology. Raymond (1977) indicated that “the biochemical characterization of many metal‐containing systems, and the application of new and powerful physical tools has made the research area described as ‘biolnorganic’ one of the fastest moving in chemistry.” Neilands 1977) stated that “until recently the problem of iron assimilation in microblal species could be likened to a quiet, pastoral scene with a few low powered microbiologists and biochemists patiently tending their crop. Just in the past 2 years, however, this scene has changed radically, by the sudden shift of emphasis from structural chemistry and fungi to membrane physiology and enteric bacteria.” These same type ‘quiet pastoral scenes’ have existed in plant nutrition as related to physiological, biochemical, genetic and agronomic practices associated with plants. Any plant vas just a plant and treated as though each plant responded nutritionally like others in any given environment. This scene is rapidly changing with the gradual recognition that plants are functionally diverse, dependent on their past genetic adaptation to conditions that prevailed in their respective innate habitats. What does this mean to the scientist? Can we take plants or plant parts from their innate habitat and subject them to drastically different environments and expect to generalize from the results obtained? For example, SC369–2–1 sorghum grew well on an acid Bladen (Typic, Albaquults) soil (Fig. 1, bottom left) but developed Fe chlorosis on an alkaline Quinlan (Typic Ustrochrepts) soil (Fig. 1, top left). In contrast, NK212 sorghum responded exactly opposite to SC369–3–1 when grown on the two soils (Fig. 1, right) (Brown et al., 1977). What are the physiological and biochemical differences inherent in these two sorghum genotypes and how may these differences affect specific biochemical processes, i. e. photosynthesis or nitrogen metabolism? Many physiological and biochemical reactions are influenced or controlled by nutrient elements. A new era in plant nutrition is opening the door to an understanding of genetically contained factors in plants that were acquired when the plants were subjected to different environmental habitats. These factors affect everyone involved with propagating plants or determining growth processes vital to crop production.