Effects Of Growth Characteristics Of Phlox Subulata L. Under Different Shading Conditions

Phlox subulata L. is perennial flowers of Polemoniaceae Genus Phlox. Due to the strong resistance, high coverage and high ornamental value, Phlox subulata L. gradually become good for gardening materials in our landscaping. There are a lot of space multilayer structure in the garden arrangement and the light is the main factor limiting plant growth for the lower part of the plant in the multilayer structure of space. This paper studied different shading treatments (shading degree 0,25%,40%,60%,80%) to Phlox subulata L. growth and development, anatomical structures and physiological indicators and so on to study different shading treatments about 'Baitan' and 'Juhuameihong'which are two cultivars of Phlox subulata L. on the growth characteristics with a view to provide a scientific basis for the application of Phlox subulata L. in landscape configuration. The main findings are as follows.1 With the increase of shade intensity, the leaves of Phlox subulata L. became darker in color, florescence extended gradually, flowering amount increased and flowering was delayed; the color of 'Juhuameihong' flower deepensed and the longest flowering occured at 60% shade treatment. The plant height and crown width of Phlox subulata L. increased with the increase of shade intensity. The results showed that the 80% shade treatment was the most conducive condition to the growth of'Baitan' and the 60% of shading on the 'Juhuameihong'flower was the best growth condition. Thus, the moderate shade could make two species grow better.2 Leaf of the two materials are composed of three parts namely the epidermis, mesophyll and vascular bundle. With the increase of shading intensity, the leaf thickness, the leaf epidermal thickness, palisade tissue thickness and spongy tissue thickness turned thinner, the ratio of palisade tissue and spongy tissue thickness decreased. Two cultivars of Phlox subulata L. leaves palisade tissue was less than others at the condition of 80% shade. Therefore, Phlox subulata L. leaves have a strong ability to adapt the internal structure of the blade.3 With the increase of shading intensity, the content of leaf water content, chlorophyll a, chlorophyll b, chlorophyll (a+b) increased gradually, the membrane permeability, chlorophyll a/b value, the content of malondialdehyde (MDA), proline (Pro), soluble protein, soluble sugar decreased gradually. The content about 'Juhuameihong'of chlorophyll a, chlorophyll b, chlorophyll (a+b) was the highest and the membrane permeability, chlorophyll a/b value was the lowest at the condition of 60% shade.The chlorophyll fluorescence parameters PS (?) photochemical efficiency (Fv/Fm) and Photochemical quenching (qP) of two cultivars of Phlox subulata L. increased and non-photochemical quenching coefficient (qN) decreased with the increase of shading intensity. It was more beneficial for 'Baitan' to do photosynthesis at the condition of 80% shade. While he condition of 60%?80% shade was more beneficial for 'Baitan'to do photosynthesis.In summary, two cultivars of Phlox subulata L. grew better when'Baitan' and' Juhuameihong' at the condition of 80% and 60% shade. It is important to extend the growing season and the viewing period of Phlox subulata L..