Study On The Morphological And Physiological Response Of Phosphorus Foraging Process By Neyraudia Reynaudiana

Phosphorus is one of the most important nutrient elements and necessary for plant growth and development.It plays a vital role in biosynthesis and transport,material metabolism and other physiological process.Available phosphorus is mainly absorbed from the soil by plants,that is low in the soil of southern China and can not meet the needs of plant growth.Moreover,P is highly heterogeneous in the soil environment.Plants need to find more nutrient resources from the soil and can form a certain foraging behavior to meet the growth need.Phosphorus foraging behavior of plants is one of the most important theories to reveal the survival of plants under low-P environment.Therefore,the study on this behavior has become a hot topic in botany theory.Neyraudia reynaudiana is an excellent pioneer species of soil erosion area in the south of China,and known for strong stress resistance,wide ecological amplitude and other excellent characteristics.It plays an important role in soil and water conservation,slope management and soil pollution remediation.At present,the research on N.reynaudiana mainly focuses on the aspects of stress resistance and ecological applications.N.reynaudiana can grow in extremely harsh and barren soil environments,that is an adaptation characteristic formed during the long-term evolution,and may have special foraging mechanisms.However,the way that N.reynaudiana finds nutrients from the heterogeneous environment is not clear.In view of this,this paper uses N.reynaudiana as experimental material,constructs different P patch size and patch distance,and applies dynamic sand culture experiment of 3 stages to study the morphological and physiological characteristics of P nutrient foraging behaviour of N.reynaudiana and provide scientific basis for efficient utilization of soil P nutrient.The main results are as follows:(1)The morphological response of P patch size on N.reynaudiana:when the P supply level of N.reynaudiana was the same,the shoot height in 3 stages,the ground diameter and biomass of each organ in the middle and late stages,and root length,root surface area,root volume,root average diameter in the late stage were highest at the large patch,and lowest at the small patch.The tiller number and leaf number in the middle and late stages were highest at the large patch of P.Besides,the root surface area in 3 stages and root length and root volume in the middle and late stages of N.reynaudiana were higher in the P-enriched patch than P-poor patch.(2)The physiological response of P patch size on N.reynaudiana:in the late stage,the chlorophyll a and total chlorophyll were highest at the large patch,the P content of each organ was highest at the small patch.The P allocation amount of each organ was large patch>medium patch>small patch,the leaf MDA content and root acid phosphatase was highest at the large patch in 3 stages.Besides,when the P supply level of N.reynaudiana was the same,the P content in stem and leaf was higher in the early stage,the P content in leaf was higher in the middle stage,and the P content was leaf>root>stem in the late stage;the P allocation amount was leaf>stem>root in 3 stages.(3)The morphological response of P patch distance on N.reynaudiana:in the original environment of P deficiency,when low P in the near distance and high P in the remote distance,the root length,root surface area and root average diameter were higher at the near distance patch in the early and middle stages,while they were higher at the remote distance patch in the late stage;and the root volume was higher at the remote distance patch in 3 stages.In the original environment of P deficiency,when high P in the near and remote distance,the root length was higher at the remote distance patch,and root average diameter was larger at the near distance patch in 3 stages.In the original environment of low P,when high P in the near and remote distance,the root length,root surface area,root volume and root average diameter were higher at the near distance patch in 3 stages.Besides,the root biomass was lower than stem and leaf biomass in 3 stages.(4)The physiological response of P patch distance on N.reynaudiana:in the middle and late stages,the root acid phosphatase in T13 and T14 was higher at high P patch in the remote distance,and the root acid phosphatase in T15 was higher at high P patch in the near distance,the P content of each organ was higher at T14 and T15.The P allocation amount of each organ was highest at T14 or T15.Besides,in the early stage,the P content was lowest in root and the P allocation amount was root<stem<leaf;in the middle stage,the P content and P allocation amount was highest in root;in the late stage,the P content was stem<leaf<root and the P allocation amount was highest in leaf.