| For the situation of poor adaptation, poor performance, serious degradation of cold and warm season turfgrass species in the transitional climatic zone to screen lawn grass and cultivate strong resistance varieties relying on the rich wild plant germplasm resources in Southwest China. In this paper Art. Hoo. was the test materials, and it’s stem and leaf traits, plant bush types, regenerative were conforming with the requirements of the turfgrass. Used random district group test design and through human to set drought(4 gradient) and shading(5 gradient) collaborative processing gradient to analysis the growth characteristics, component traits, biomass accumulation and morphological plasticity of the Art. Hoo. under the drought and shading collaborative processing, and study on the chlorophyll content, anti-oxidation enzyme activity and the change of photosynthetic parameters of the Art. Hoo., which aimed at discussing the coping strategies and adapted degrees under the habitat stress to provide the basis for the utilization and development. The results were as follows:(1)Component traits:The stress of shading and drought had a certain effects on the component traits of Art. Hoo.. Shading on leaf raits, stem traits, root traits were significantly affected, and the effects of sequence as follows: stem traits > leaf traits> root traits. With the increase of the shading degree, the leaf traits, plant height, internode length were increased, and those were more under 70% shading. The longest root length, root numbers per plant,gas rooting were decreses with shading increases. Drought stress had lagder effects on root that the number and length of root were increased, and the longest root was 49.16 cm in W3 under the CK, and higher than those of the other the longest root length. The number of roots per plant for 14.33 in W2 under the CK, and more than other root number. Primary branches and secondary branches were increased with the shading and drought stress reduced. By increasing the growth of the ground to resist the lack of light,by increasing root traits to resist drought stress.(2)Biomass accumulation:The stress of shading and drought has effect on the biomass accumulation of Art.Hoo.. Shading had significantly effects on the stem, leaf and root biomass(P<0.01).The leaf biomass in the shade ware higher than the CK, and the leaf biomass accumulation reached 1.05 g and was highest under the shading of 50% and W0;Shading conditions and drought stress had less leaf biomass accumulation, and the leaf biomass only 0.23 g under the CK and W3 stress. Shading had also contributes to the increase of stem biomass, and the stem biomass reached 1.42 g in W0, and was the highest under the shading of 50%. The root biomass in W2 stress was higher than W0,and the root biomass was maximum under the CK and W2. The root cap ratio is relatively small under drought and shading conditions, and the big root shoot ratio was1.16 under the CK and W2, while the less root cap ratio was 0.53 under the CK and W0,and it was only 0.10 under the shading of 70% and W0, that indicating under drought conditions making appropriate shading have beneficit on the growth of the aerial parts.(3)Enzymatic activity:The stress of shading and drought had significantly effects on SOD, POD, CAT activity(P<0.01). The SOD, POD and CAT activity had increase under moderate stress of shading and drought. The SOD activity reaching 348.80 U·min-1·g-1,and was the highest under the combined stress of shading of 50% and W2. POD and CAT activity were highest under the combined stress of shade of 10% and W2, and respectively were715.00 U·min-1·g-1 and 121.26 U·min-1·g-1. When the stress of shading and drought more than the moderate range, the enzyme activity were decreaseing. The plants will be by regulating the activity of the enzyme to resist the lack of light and water to let the plant from damage when less than the stress range of shading of 50% and W2. The enzyme activity reached a peak and then decreased, the resists ability of stress had drops, and reached the largest plant tolerance limits under the stress of shading of 70%and W3.(4) Metabolites:The stress of shading and drought had significantly effects on the content of MDA(P<0.01). The content of MDA content was minimum under the shading of 10%, while the plants have been hurt when the content of MDAwas maximum under the shading of70%. The content of MDA has been rising under the stress of drought, it is said that the plant has been hurt under the stress of drought. The stress of shading and drought, the content of MDA was small under the stress of the shading of 10%, and the content of MDA was more under the stress of shading of 70% and W3,those said hat it can increase the drought resistance of plants under the stressof mild drought make proper shading.The stress of shading had significantly effects(P<0.01) on the Proline(PRO),Soluble Protein(SP) and Soluble Sugar(SS). The shading had the greatest effect on Soluble Sugar, and SS have been decreased under the conditions of shading; PRO and SP under the stress of shading were more than CK. The stress of drought had larger effect on the SP, and the SP reached maximum under the conditions of the shading of30% and W2,and was 30.84 mg·g-1. The PRO and SP were larger under the stress of drought in W2,and indicating Art. Hoo. can endure the drought environment less than W2.(5) Chlorophyll:The stress of shading had significantly effects on chla, chlb, chla+b and chla/b(P<0.01), and those were highest under the stress of the shading of 70%; The stress of drought had significantly effects on chla,chlb, chla+b and chla/b(P<0.01), and those were reduction with the stress of drought aggravated; The stress of shading and drought has the greatest effect on the content of chlb, chla/b,and in W3,the content of chlb under the shading of 70% was higher than that of CK, and it is incidating that under drought stress make appropriate shading was contributes the elevation on the content of chlb, and was beneficial to improve the photosynthetic efficiency.(6) Gas exchange parameters:The stress of shading and drought had significantly effects on the gas exchange parameters(P<0.01). Under the shading condition, the net photosynthetic rate(Pn),stomatal conductance(Gs), transpiration rate(Tr) were higher than that of CKwhen the shading was 10% and 30%, while were lower than that in CK when more than the shading of 30%. It is said that the appropriate shading can contribut to increase net photosynthesis of the Art. Hoo.. The net photosynthesis rate was decreased under the stress of drought, and under the stress of drought, the net photosynthesis under the shading of 10% and 30% was higher than that of CK. The net photosynthesis rate was largerest under the stress of the shading of 30% and W0, and had no difference between W1 and W2 under the same shading. The light saturation point was minimum under the shading of 70%; The light compensation point was minimum and the net photosynthetic rate was maximum under the shading of 30%. The light saturation point and the maximum net photosynthetic rate under W0 were lower than W3. Under the stress of drought making shading treatment, the light saturation point and light compensation point was lower than CK when less than the shading of 50%, and the maximum net photosynthetic rate was higher than that of CK when less than the shading of 50%, so under the stress of drought making proper shading can improve the rate of the light utilization.In summary, the Art. Hoo. can make normal metabolic activity of life under the range of the shading of 30% and the stress of drought in W2. Now the city gardening in green building, the lack of water and shading become factors restricting to the development of turfgrass greening plants. The poor of abaptability of introduction of turfgrass resulting in a serious degradation of the turfgrass, and reducing the effect of landscape lawn. Art. Hoo. was a better turfgrass selection of varieties in the area of drougth and shading for certain resistance to drought and shading. |
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