The Effects Of Temperature And Trimming On Morphological Plasticity And Physiological Stress Of Arthraxon Hispidus

In view of the practical problems of low turf landscape value,high conservation cost and short life span caused by the poor wintering and summering ability of the turfgrass introduced in the transitional climatic zone,the local wild resource（Arthraxon hispidus（Thunb.）Makino.）was used as the experimental material,the main cold-season turfgrass（Festuca elata Keng ex E.Alexeev）as the control grass species in this paper.Analyzed the morphological plasticity and physiological stress of valerian under high temperature and trimming and studied on the difference of heat resistance and trimming resistance between Arthraxon hispidus and(Festuca elata Keng ex,which aimed to lay the foundation for the development and utilization of native wild turfgrass resources.The results showed that:（1）component traits of Arthraxon hispidusTemperature had significant effects on leaf,stem and root traits（P<0.05）,all traits decreased with the increase of the temperature degree.It has a great influence on leaf traits and root traits:The leaf traits decreased significantly with the increase of temperature under low trimming.The length and number of roots decreased significantly at T₃₀,while the stem traits had no significantly decreasing.Trimming had significant effects on leaf,stem and root traits（P<0.05）.Leaf traits decreased significantly with the increase of the trimming degree at T₃₀0 and T₃₅,and decreased most at T₃₅.The number of tiller increased at H₁₀0 and H₆ when T₂₅5 and T₃₀0 temperature.The root length decreased significantly with the increase of trimming,while the other root traits showed no significant difference.The traits were significantly reduced under the T₃₅H₄ treatment combination under the combined action of temperature and trimming.It shows that low trimming under high temperature will increase the inhibition of plant growth,and appropriately increase the height of trimming can reduce the damage caused by high temperature.（2）Biomass of Arthraxon hispidusTemperature had a significant effect on biomass（P<0.05）,leaf and root biomass decreased most significantly at T₃₅.Stem biomass decreased significantly with the increase of the temperature at low trimming.There was no significant difference in root-shoot ratio with the increasing of the temperature at H_ckk but decreased significantly at other trimming degrees;Trimming had significant effects on leaf,stem,and root biomass（P<0.05）,and had no significant effect on root-shoot ratio.Leaf biomass and root biomass decreased with the increasing of the trimming.Stem biomass increased under certain trimming degree at T₂₅,indicating that trimming would promote stem biomass increase.The leaf and stem biomass and root-shoot ratio were the highest at T₂₅H₆,and each index was the lowest at T₃₅H₄.It shows that high temperature and low trimming inhibit each other.Arthraxon hispidus can keep the balance of aboveground and underground biomass by increasing stem to resist the stress of high temperature and low trimming.（3）Enzyme activityTemperature had a significant effect on the activity of SOD,POD and CAT of Arthraxon hispidus（P<0.01）,which decreased with the increase of temperature,decreased significantly at T₃₅.Trimming had a significant effect on SOD,POD,and CAT activities（P<0.01）,which increased first and then decreased with the increase of trimming,highest at H₆.Under the conditions of T₂₅5 and T₃₀,the enzyme activities at H₁₀,H₆,H₄ were higher than H_ck,while at H₄ were significantly lower than H_ckk under T₃₅.The synergistic effect of temperature and trimming had significant effects on SOD,POD and CAT enzyme activities（P<0.05）.which were significantly higher at T₂₅H₆.（4）MetabolitesThe temperature had a high significant effect on MDA,PRO and SS in Arthraxon hispidus（P<0.01）.With the increase of temperature,the content of MDA decreased significantly and PRO increased first and then decreased.The content of SS increased at H_ckk and H₄,decreased first and then increased H₁₀0 and H₆.Trimming also had a high significant effect on MDA,PRO,and SS（P<0.01）.With the increase of trimming,MDA content increased first and then decreased,was the highest at H₆,PRO content decreased first and then increased,and the content was the lowest at H₁₀.SS content increased first and then decreased,and the content was the highest at H₁₀.（5）Turf qualityTemperature had a significant effect on the density,color,texture and uniformity of Arthraxon hispidus（P<0.01）,and had the greatest effect on color.The evaluation indexes decreased with the increase of temperature and had the best apparent traits at T₂₅.The composite score was significantly lower at T₃₅.Trimming had a significant effect on density,color,uniformity,and comprehensive score（P<0.01）.The indexes at T₂₅5 and T₃₀0 had a certain degree of improvement after trimming treatment,changed more significant at T₂₅,and there was a significant downward trend at T₃₅.The synergistic effect of temperature and trimming had significant effects on density,uniformity and comprehensive score（P<0.05）.The overall performance was best in T₂₅H₆.The comprehensive score at T₃₅H₄ was the lowest.（6）Comparison of Arthraxon hispidus and Festuca elata Keng exThe characteristics of Festuca elata Keng ex components were greatly affected by temperature.At T₂₅5 temperature,the traits,enzyme activities and secondary metabolites of Arthraxon hispidus and Festuca elata Keng ex were in excellent condition,when the temperature increased to T₃₀,all traits were found decline,Arthraxon hispidus decreased less than that of Festuca elata Keng ex.Arthraxon hispidus still grew better at T₃₅,which was the limit temperature that Festuca elata Keng ex could withstand,indicating that Arthraxon hispidus is more resistant to high temperature than Festuca elata Keng ex.The growth of Arthraxon hispidus and Festuca elata Keng ex in stems and the number of tillers increased at H₁₀0 and H₆,inhibited at H₄,the inhibition of Festuca elata Keng ex was much heavier.Especially at T₃₀0 and T₃₅,Festuca elata Keng ex suffered the most from low trimming.Low trimming at T₃₅5 can cause irreversible damage even death.Therefore,Arthraxon hispidus has stronger pruning resistance than Festuca elata Keng ex.