Khwaja and Roy [4] have given nutrient ranges in ginseng based on extensive sampling of growers’ fields. Minimum and maximum B concentrations in leaves of 2–4-yr-old plants were: 5 μg/g, deficient; 5–15 μg/g, low; 16–50 μg/g, sufficient; 51–100 μg/g, high; and >100 μg/g, excessive. Konsler and Shelton [5] and Konsler et al [6] described the effect of lime and phosphorus on the growth, nutrient status, and ginsenoside content of the ginseng root. Ginseng production in Ontario, Canada, the major center for American ginseng culture,

is on sandy and sandy-loam soil with low organic matter content, along the north shore of Lake RGFP966 cell line Erie [7]. In general, these soils are low in B for production of many crops [8] and [9]. Previously, we reported that the rusty root of ginseng and associated internal browning of roots grown in the above-mentioned soils may be linked to B deficiency [10]. B is required by plants only in small amounts, therefore, overapplication CCI-779 mouse to crops can occur easily.

Oliver [11] recommended that to maintain adequate soil levels of B for ginseng cultivation, 1–2 kg/ha should be applied when soil tests show ≤0.5 μg/mL. B is taken up through the plant roots as boric acid and transported with the transpiration flow. In most plants, B is highly immobile [12], being restricted to the transpiration stream. Accumulation of B can occur at the end of the transpiration stream in the leaves [13]. Manifestation of B toxicity shows as damage to tissues where it accumulates. Although B toxicity is crop-specific, learn more it generally leads to chlorosis and necrosis starting at the edges of mature leaves [12] and [13]. This development of necrotic areas can reduce leaf photosynthetic potential, cause a reduction of photosynthetic supply to the

developing root system, the economic part of the ginseng plant, and restrict activity in the meristematic tissues. It is unclear why B is toxic to plants, or why some plants can tolerate B and evade toxicity [13]. Reid et al [14] concluded that, at high B concentrations, many cellular processes are retarded and these are often made worse in light by photoxidative stress. Ginseng is a perennial plant requiring about 4 yr from seeding to root harvest, therefore, we examined the possibility of using radish as a time-saving model system in our B nutritional studies. Radish requires 3–6 wk from seeding to root harvest and B deficiency induces root splitting and brown heart disorder [15], similar to brown heart in ginseng [10]. Also, B toxicity in radish reduces root growth [16] and [17]. Lack of definitive data on B nutrition of American ginseng, the supposed deleterious effects on the leaves, roots, and meristematic regions, and an application of a high concentration of B to commercial ginseng plantings prompted this investigation.