Screening for drought resistance among ornamental maples (Acer sp.). A field experiment in juvenile plants

Urban greenery is often affected by adverse environment (including inadequate water availabil-ity) of human agglomerations. Besides high aesthetic value, maples (Acer sp.) with elevated resistance to air/soil pollution, have become common components ornamental plantations in Europe. Because theoretical (representativeness for species evaluation) and practical (planting age) relevancy, morphological metabolic reactions juvenile plants eight maple one month long summer drought were studied the experimental field estimate resistance. In spite marked growth differences, none from tested showed a significant decrease leaf relative content indicating stress. However, some them activation protective mechanisms was observed, what points past stress sensing. A. negundo tataricum bet on transpiration area reduction (leaf shedding) buergerianum, palmatum saccharinum osmotic adjustment (increased free proline concentration). Increase stomatal index and/or specific area, observed almost exclusively continuous growth, had limited effect plant hydration status. Relative trunk par-ticularly fast growing species. Taking into account decisive onset stability, can be ordered respect as follows: campestre, monspessulanum, platanoides, tataricum, negundo, saccharinum, buergerianum.