Water Physioecological Characteristics And Evaluation Of Six Magnoliaceae Tree Species

Magnoliaceae tree species is one of the major urban afforestation tree species in China,and it has good ecological adaptability and utilization prospects.However,the research basis for the water physiological and ecological characteristics of most tree species is currently weak.This study have take six tree species for test material,which of Manglietia grandis,Michelia sirindhorniae,Manglietia maguanica,Manglietia aromatica,Parakmeria yunnanensis and Pachylarnax sinica.Using theories and techniques of plant anatomy,plant physiology,and biochemistry,the tissue anatomy and water physiological and ecological parameters of each tree species were observed and determined to clarify and evaluate the water-tolerance characteristics,and the selection of urban garden trees in South China was studied.Configuration provides technical guidance.The results as follows:(1)The mean water content of the leaves,stems and roots of the tested trees was 76.80%,70.64% and 83.39%,respectively.Among them,the largest Leaf tissue moisture content was Manglietia aromatica;the largest Root tissue moisture content,Leaf tissue moisture content and Stem tissue moisture content were all Michelia sirindhorniae,but the leaf water saturation loss of Michelia sirindhorniae was lowest.(2)The average daily water consumption of the seedlings of the tested trees was 52.3 g.The largest total water consumption,155.6g,was Michelia sirindhorniae.(3)In morphological anatomy,the largest root endothelium thickness,root plenum thickness,stem air cavity area,stem air cavity ratio and leaf palisade tissue were Manglietia grandis;The largest root air cavity area was Michelia sirindhorniae;the largest root air cavity ratio,leaf upper epidermis and lower epidermis thickness were Parakmeria yunnanensis;the largest leaf sponge tissue thickness,leaf air cavity area and air cavity ratio were Pachylarnax sinica;the largest stem formation thickness was Manglietia maguanica.(4)The daily changes in the net photosynthetic rate of all tested trees showed a ?double-peak? pattern.The order from big to small is: Manglietia maguanica>Manglietia grand>Michelia sirindhorniae>Parakmeria yunnanensis>Pachylarnax sinica>Manglietia aromatica.The daily changes in transpiration rates of the tested trees were both ?bimodal‘ and ?unimodal‘.Manglietia grandis,Manglietia maguanica and Parakmeria yunnanensis were ?bimodal‘.Michelia sirindhorniae,Manglietia aromatica and Pachylarnax sinica were ?unimodal‘.The order of daily transpiration rate of each species tested from big to small is: Michelia sirindhorniae>Manglietia maguanica>Pachylarnax sinica>Manglietia aromatica>Parakmeria yunnanensis>Manglietia grandis.The order of water use efficiency of each tree species was as follows: Manglietia aromatica>Manglietia grandis>Pachylarnax sinica>Parakmeria yunnanensis>Manglietia maguanica>Michelia sirindhorniae.(5)The light saturation point of each test tree species is as follows: Michelia sirindhorniae>Manglietia maguanica>Pachylarnax sinica>Manglietia grandis>Parakmeria yunnanensis>Manglietia aromatica.The light compensation points for the test trees are as follows: Manglietia grandis>Michelia sirindhorniae>Parakmeria yunnanensis>Manglietia maguanica>Pachylarnax sinica>Manglietia aromatica.(6)The relative conductivity of the tree species showed an upward trend with the increase of the infusion time.The maximum relative electrical conductivity of each tree species from the largest to the smallest was: Pachylarnax sinica >Manglietia aromati>Manglietia maguanica>Parakmeria yunnanensis>Manglietia grandis>Michelia sirindhorniae.In the process of flooding,the maximum decline ratio of Fv/Fm and Yield were Manglietia maguanica,minimal was Michelia sirindhorniae.(7)Comprehensive analysis and evaluation of each parameter index using principal component method,The order of the water-tolerance of the six tree species from strong to weak is: Michelia sirindhorniae?Manglietia grandis?Manglietia maguanica?Manglietia aromatica?Pachylarnax sinica?Parakmeria yunnanensis.Michelia sirindhorniae shows excellent water-tolerance and its water physio-ecological adaptation mechanism needs further study.