In vitro shoot bud induction and multiplication as well as plantlets formation from different parts of 21-d old seedlings (shoot tip, cotyledonary node, distal part of cotyledon, acropetal section of hypocotyl) of Capsicum annuum L., cv. Bryza were compared. During 4 weeks of primary explant culture on initiation media, first shoot bud primordia appeared; they reminded leaf primordia and subsequently some of them underwent enlargement, some developed into leaves and leaf-like structures (mainly on cotyledon explants). The highest number of shoot bud primordia was noted on cotyledonary node explants, but they were smaller than those on the remaining types of the explants. The best response of shoot regeneration showed cotyledon explants on which most of shoot buds were formed in each from four treated passages. From shoot buds on elongation media after 4 weeks of culture rooted rosettes of leaves were achieved, and the extension of the culture time to eight weeks without subculture caused that the rosettes developed into plantlets. Throughout four successive passages plantlets were obtained from cotyledon and shoot tip explants

Abstract. The aim of the study was to evaluate the content of Zn, Cu, Mn, Pb, Hg and Fe in sandy everlasting, yarrow and stinging nettle in relation to the concentration of metals in the soil. Samples of soils and plants were collected from natural habitats (edges of forests in the Kujawy-Pomerania Province). The total metal content and their available forms for plants in the soil samples were determined. The stinging nettle inhabited the richest environmental areas in which anthropogenic accumulation of metals in the surface of soils was determined. The investigated soils were not contaminated with heavy metals and the content of their plant-available forms was not harmful for a proper plants growth. The content of metals extracted with the diethylenetriaminepentaacetic acid was considerably higher than the concentration referred to as the deficit level for plants. Among the analyzed herbal plants, sandy everlasting contained the largest amounts of copper, manganese, and only concentration of lead in dry weight was higher than 10 mg⋅kg -1 , indicating that the plants harvested from the study areas should not be used in herbal medicine. Bioconcentration factor (BCF) values point clearly to the mercury and zinc accumulation in the aboveground parts of herbal plants.

Adventitious shoots differentiated directly from explant tissue without intermediate callus on all types of examined explants (shoot tip, cotyledonary node, cotyledon and hypocotyl) of Capsicum annuum L. cv. Bryza. First cell divisions took place as early as after 3 days of explant culture within epidermal and subepidermal layers of explants, and in the case of cotyledon also within mesophyll cells located near epidermis. Mitotic activity in these layers led to the formation of meristemoids (meristematic centres). In all types of studied explants, meristematic centres appeared approximately at the same time (after about 7 days of culture). In the second week bud primordia began to differentiate from meristematic centres. Subsequently some of shoot primordia developed into leaves and leaf-like structures (mainly on cotyledon explants), and also into adventitious buds with well developed apical meristem and leaf primordia

The common trait of all auxins is a stimulation of cell elongation and also cell division in the presence of cytokinin; both are essential for callus induction and its multiplication. The response of plant tissues to various compounds with auxin activity may be quite different. In this study, the effectiveness of a synthetic auxin, 2,4-dichlorofenoxyacetic acid (2,4-D), instead of the generally applied natural auxin, indole-3-acetic acid (IAA), was tested for the proliferation of Nicotiana tabacum callus. The following concentrations of 2,4-D were tested: 0.1, 0.5, 1.0, 1.5, and 2.0 mg dm −3 . Callus was derived from stem pith and its proliferation allowed on MS medium through five subcultures at 25°C and in darkness. After each passage, the fresh weight and morphological features of the callus were determined. The 0.5 mg dm −3 2,4-D treatment was the most favorable for producing the greatest increase in fresh weight in each of five subsequent subcultures as well as maintaining normal morphological features for proliferation. However, the 1.0 mg dm −3 2,4-D treatment in comparison with the lowest, 0.1 mg dm −3 , was more beneficial when considering regular increases of fresh weight and a better cell cohesion for callus growth.

Regeneration capabilities of Capsicum annuum cotyledons and leaves were compared. Adventitious buds, leaf like structures and callus formation occurred on both types of explants, roots on cotyledons only. Murashige and Skoog basal medium containing 1.0 mg dm^-3 indole-3-acetic acid (IAA) and 1.0; 5.0; 10.0; 15.0 mg dm^-3 6-benzylaminopurine (BAP) were used. Adventitious buds were induced more frequently on cotyledons than on leaves. The middle part of cotyledon explants and the distal part of the leaf explants seem to be the best