Preliminary Studies On Drought Resistance Of The Ground-cover Chrysanthemums

The ground-cover chrysanthemum is a sort of perfect ground cover plants with many resistances. It acts as an important role for the virescence in the northern areas of China. Most of the ground-cover chrysanthemums are with very strong drought resistance through forty years' selection and cultivation, but how much ultimate water does the ground-cover chrysanthemums need? This paper will discuss the problem and give the preliminary results.The paper researched drought resistance and water saving of 'Xin Hong' 'Ba Long' 'Luo Jinqian' three ground-cover chrysanthemums and 'Yang Guang' 'Xi Wangju' two Beijing mini-chrysanthemums by mensurating physiological and formal indices related with drought resistance. At last a comprehensive evaluation on drought resistance of different cultivars was given according to subordinate function values analysis.The paper consists of three parts, i.e. drought resistance research, water saving research and comprehensive evaluation on drought resistance.Drought resistance research concluded seeds germination in different PEG concentration, cuttings membrane permeability under drought stress, water losing rate and leaf water conservation in different cultivars, leaf relative water content and characteristics of anatomical structure and stomata apparatuses. In addition researched drought resistance of different cultivars in different soil component.Water saving researched the ultimate water quantity and biomass of different cultivars.Finally, a comprehensive evaluation on drought resistance of different cultivars was given according to subordinate function values analysis.The result was that all of the four cultivars being highly drought resistance except 'Xi Wangju'. The difference among them was not significant. The ultimate soil water content required is 5.9%-6.9%, being much lower than 9%, the common soil water content. Under potted condition only 6000-7000ml can be needed and 8000-10000ml can satisfy it growing normally. In practice, during the whole growing season the ground-cover chrysanthemums have become recovered after transplanting, they need not supply more water.