| Ornamental grass is a relatively new landscaping material in our country, due to its natural, high visual value and drought-enduring, barren-enduring, disease-resistant, pest-resistant, low management demand properity, ornamental grasses become widely.used in China. Nanjing locating at the Yangtze River delta in China, which climate is very special. The temperature is high and rainy during summer, while in winter the temperature is low and damp. Thus, it is vital to select the proper grasses adaptive in Nanjing. Research on the biological characters, visual characters and the stress enduring mainly give quantitative descriptions, instead of qualitative descriptions. Considering the above situation, the thesis mainly study on the biological characters, visual characters and the drought-enduring of the thirteen ornamental grasses in Nanjing, with an aim to provide theoretical evidence for the introduction, cultivation and landscaping in Nanjing and even in the Yangtze delta. The main results are as follows:1. The systematical observation of phenophase, morphological characters, over-summer ability, over-winter ability, the ability of disease-resistance and pest-resistance of the thirteen ornamental grasses shows some results as follows:as far as the eight warm-season ornamental grasses are concerned, except for Sella Pampasgrass and ’Ever-gold’Sella Pampasgrass are evergreen, the rest six grasses are withered and yellow at the end of November. Lemon Grass turns green in the beginning of May, while Janpanese blood grass, Maiden grass, Variegated miscanthus, Zerbra grass and Chinese Pennisetum turn green at the end of March. Lemon Grass and Janpanese blood grass do not blossom in Nanjing, while the anthesis of the other six grasses are long, which concentrate on from July to November. As for the five cool-season ornamental grasses, Finesterm Needlegrass and Blue Fescue hibernate in summer, Gardener’s garters experience a short-term hibernation in winter,’Ever-gold’Sedge and Golden variengated sweet flag are evergreen. The anthesis of the five cool-season grasses is shorter than the warm-seasoned grasses; concentrate on from March to June. Fortunately, apart from some aphids appear in Gardener’s garters during the mould rains season in early summer, others do not show diseases and insect pests, so the ability of resisting the diseases and insect pests of the thirteen ornamental grasses are relatively strong.Two kinds of cool-season grasses, which are’Ever-gold’Sedge and Golden variengated sweet flag, and eight kinds of warm-season grasses have strong adaptability in Nanjing. Blue Fescue and Finesterm Needlegrass are fit to be used as the landscaping material in spring and winter in Nanjing. In view of Gardener’s garters’reproduction mode is Roots-type breeding, its ability of intruding the growing space is more powerful, thus, is prone to lead to intraspecific competition. Therefore, some necessary actions should be taken to avoid this phenomenon.2. Using the Gray correlation analysis method to evaluat the ornamental value of the thirteen ornamental grasses during the whole four seasons, then got the ornamental values of the thirteen ornamental grasses in spring from high to low are as below:Finesterm Needlegrass, Blue Fescue, Janpanese blood grass, Zerbra grass, Maiden grass, Golden variengated sweet flag, Variegated miscanthus,’Ever-gold’Sella Pampasgrass, Sella Pampasgrass,’Ever-gold’Sedge, Chinese Pennisetum, Gardener’s garters, Lemon Grass. Lemon Grass’s ornamental value is not so high because it turns green too late, while the others and the Gray-correlation analysis between the other grasses and the ideal grass is over0.65. The order in summer is:Chinese Pennisetum, Janpanese blood grass,’Ever-gold’ Sella Pampasgrass, Zerbra grass, Lemon Grass, Variegated miscanthus, Maiden grass,’Ever-gold’Sedge, Gardener’s garters, Golden variengated sweet flag, Finesterm Needlegrass, Blue Fescue. The order in autumn is:Sella Pampasgrass, Zerbra gras,’Ever-gold’Sella Pampasgrass, Chinese Pennisetum, Janpanese blood grass, Variegated miscanthus, Maiden grass, Gardener’s garters, Lemon Grass,’Ever-gold’ Sedge, Golden variengated sweet flag, Finesterm Needlegrass, Blue Fescue. Because of the hibernation of the six species warm-season ornamental grasses, the order in winter is:Blue Fescue,’Ever-gold’Sedge,’Ever-gold’ Sella Pampasgrass, Golden variengated sweet flag, Sella Pampasgrass, Finesterm Needlegrass, Gardener’s garters.Different ornamental grasses have different ornamental seasons and different ornamental parts. For landscaping application, suitable ornamental grass can be choosen according to ornamental characteristics and ornamental seasons. In spring, Finesterm Needlegrass are blooming, with beautiful rhythm and peculiar motion in the wind, and its fine bright green stems and leaves, so spring is the best ornamental time for Finesterm Needlegrass. Blue Fescue hibernates in summer, so winter and spring are the best ornamental seasons. The leave color of Janpanese blood grass will change with the seasonal aspect, so its ornamental value is relatively high during growth and development period. Maiden grass, Variegated miscanthu and Finesterm Needlegrass bloom in autumn, thus the ornamental value are high, and the ornamental value order from high to low is Zerbra grass, Variegated miscanthus and Finesterm Needlegrass. Sella Pampasgrass and’Ever-gold’Sella Pampasgrass are also blossoming in autumn and during that time their ornamental value are obviously high.3. Using ombrophilous cultivate under the natural weather conditions in Nanjing choose six species ornamental grasses whose ornamental value are higher to proceed the drought-enduring laboratory experiment in spring. The drought-enduring ability is ’Ever-gold’Sella Pampasgrass> Lemon grass> Zerbra grass> Variegated miscanthus> Gardener’s garters> Janpanese blood grass. The results showed that the drought-enduring ability of the six different ornamental grasses were different. While, it proved that the withered leaf percentage could be used an index in the drought stress. |
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