Effects Of Shading On Photosynthesis Characteristics And Growth Of Two Kinds Of Forage

Effects of three levels of shading (0%, 50% and 75%)during different periods (60d and 120d)on photosynthetic characteristics and growth of Macroptilium atropurpurem and Stylosanthes guianensis cv.Reyan No.10 were studied.Through measurement the index of photosynthesis, content of chlorophyll, change of biomass and the other growth indexes, the following results are shown:1. Shading of 60d for Stylosanthes guianensis: It is decreased of velocity of laminae photosynthesis and transpiration, but increased of WUE. The root/shoot ratio and biomass is reduced. Also there is a significantly difference between shading treatment of 75% and CK (p<0.05). Shading promotes obvious increase of content of chlorophyll and water, also an obvious difference between shading treatment of 75% and CK (p<0.05). 75% shading of 120d for Stylosanthes guianensis: It is decreased of total content of chlorophyll, biomass, root/shoot ratio, velocity of photosynthesis and transpiration. The plant height and number of tiller are significantly less than CK (p<0.05). Water content of laminae is increased, but not much change.2. Shading of 60d for Macroptilium atropurpureum: It is decreased of biomass, stem/leaf ratio, root/shoot ratio, velocity of photosynthesis and WUE, but increased of content of chlorophyll, and also there is a significantly difference between all treatments and CK (p<0.05). Shading of 120d for Macroptilium atropurpureum: It is further decreased of biomass. It is reduced of velocity of photosynthesis, but increased of stem/leaf ratio, root/shoot ratio and WUE. There is a significantly difference between two treatments and CK (p<0.05). The content of chlorophyll is first increased, and then decreased, also an obvious difference between 50%treatments and CK (p<0.05).3. Shading has significant effect on biomass of these two kinds of forage. The effect on Stylosanthes guianensis for shading of 60d is much than on Macroptilium atropurpureum, but just on the contrary for shading of 120d. During the whole growing period, Stylosanthes guianensis gets some effect, but still can normally develop, and no withered leaves. But under long-term shading, the growth of Macroptilium atropurpureum is restrained, even some withered leaves are produced.4. Shading has much effect on overwintering of these two kinds of forage. Under the shading conditions, after the winter, the survival amount of Macroptilium atropurpureum are much more than CK, but the amount of Stylosanthes guianensis are obvious less than CK.