No abstract

Generative tillers are a source of assimilates necessary for the seed formation. However, their excessive elongation, especially under high doses of nitrogen, increases the susceptibility to lodging. The growth of generative shoots depends, among others on the root biomass affecting nutrient uptake, and on the ability to form rhizomes, as well as on the competitiveness of parallel developing vegetative tillers. Two-replicate field experiments were performed in Poland (53°09′ N, 17°35′ E), to determine the effect of plant growth regulators (PGRs) (single application of chloromequat chloride (CCC) at BBCH 30-31 or sequential treatment CCC at BBCH 30-31 + ethephon (ET) or CCC at BBCH 30-31 + trinexapac-ethyl (TE) at BBCH 37-39, and N fertilization (40 and 70 kg ha−1) on the length of generative tillers, the weight of generative and vegetative tillers, the canopy height, the weight of roots and rhizomes, and on N uptake in Festuca rubra L ssp. rubra (strong creeping red fescue) and F. r. L ssp. commutata (Chewings red fescue). Chewings red fescue turned to be more sensitive to the retardants. Generative tillers were shorter after single application of CCC as well as sequential treatment CCC + ET or TE. The tillers of strong creeping red fescue were shortened only after the application of CCC + TE. In every PGR treatments the canopy height at harvest was greater than in the control. Increasing the N rate from 40 to 70 kg ha−1 caused the reduction canopy height of strong creeping red fescue. Increased production of above-ground biomass, especially generative tillers, resulted in an increase in N accumulation in Chewings red fescue, as compared with strong creeping. Increasing the nitrogen rate from 40 to 70 kg ha−1, despite the reduction of root dry matter weight, stimulated generative tiller dry matter accumulation but it did not affect the biomass of vegetative tillers.

The experiment investigated the effect of preparations of <em>Betula pendula</em>, <em>Chamomilla recutita</em>, and <em>Urtica dioica</em> on the initial growth of <em>Hordeum vulgare</em> under laboratory conditions. The experiment involved a water solution of sap from the trunk of <em>B. pendula</em>, an infusion from <em>Ch. recutita</em>, extracts from leaves and rhizomes as well as macerated herbage of <em>U. dioica</em>, at the concentrations of 2.5%; 5%; 10% and 20%. During the first four days of the growth of the test plants, the plant preparations tested had a stimulatory effect on the length of leaves and roots in all the cases. The leaf increases were greater than those of the roots and became smaller with an increase in the concentration of the preparations. Continued watering of <em>H. vulgare</em> seedlings resulted in a further increase in leaf length after the application of <em>U. dioica</em> macerate and <em>Ch. recutita</em> infusion, with a simultaneous increase in root length with the macerate of <em>U. dioica</em> and <em>B. pendula</em> sap used at the concentrations of 2.5–10%. The other extracts made from <em>U. dioica</em> leaves and roots, irrespective of the concentration applied, strongly reduced the increase in leaves and roots from 11 to 27%. The weight of roots and leaves in <em>H. vulgare</em>, over the entire range of the concentrations applied and irrespective of the duration of the experiment, was stimulated only by <em>B. pendula</em> sap. The extracts from <em>Ch. recutita</em> and <em>U. dioica</em>, especially the leaf and root extracts, significantly reduced the root weight of the test plant.

The content of lead, zinc, copper, nickel and chromium in the aerial and underground parts of M. sinensis from eleven years old plantation and M. sacchariflorus and M. giganteus from nine years old plantations were analysed in order to recognize what organs of the plant play the most important function as a metal accumulator. It was found that in the aboveground parts, lead, zinc and copper were accumulated mostly in leaves and nickel and chromium in stems of the studied species. In underground plant parts, especially in roots, zinc, copper and nickel were most abundantly accumulated, while rhizomes accumulated higher amounts of lead and chromium. The content of lead, zinc and copper was definitely lower in those plant organs than their content in soil. The content of nickel and chromium, on the other hand, showed the opposite dependence. A similar capacity for uptaking trace elements from soil was observed for M. sacchariflorus and M. giganteus, while M. sinensis it was much lower, which is confirmed by the values of the bioaccumulation factors. The translocation factor for trace metals in the studied grass species indicated great translocation of lead and nickel from the roots to rhizomes, and that of zinc to aboveground parts.