The Study On Phenological And Functional Traits Of Common Deciduous Woody Species In The Loess Plateau

The response and adaptation of plants to the environment are concerned by ecologists.The phenology patterns and functional traits of plants both can reflect the adaptive strategies of plants to the environment.In addition,phenology also reflects the relationship between biological phenomena and seasonal climate change.Here,we investigated eight phenological traits,five morphological traits and seven stoichiometric traits of 52 deciduous woody plants(including 31 shrubs and 21 species of trees)in the Ziwuling of the Loess Plateau.Then,we compared the differences of the phenological and functional traits between trees and shrubs.The relationship between phenological characters and how the functional traits affect the phenological traits also be discussed.The main results are as follows:(1)Shrubs leaf emergence earlier and fall later,duration of leaf emergence(LE)and leaf life span(LLS)were longer than trees.Leaf area(LA),leaf nitrogen content(LNC),leaf nitrogen and phosphorus ratio(N/P)and specific leaf area(SLA)of shrubs were smaller than trees,leaf phosphorus content(LPC),leaf carbon and nitrogen ratio(C/N)were higher than trees,leaf thickness(LT)and stem density(SD)were larger than trees.(2)Leaf life span(LLS)was closely related to most phenological traits.Leaf life span was significant correlated with duration of leaf emergence(LE),duration of leaf shedding(LE)and duration of plant reproduction(R).Timing of leaf emergence(TLE)was positively correlated with ending of leaf emergence(ELE)and negatively correlated with the duration of leaf emergence(LE).Ending of leaf shedding(ELS)was positively correlated with timing of leaf shedding(TLS)and the duration of leaf shedding(LS).Duration of plant reproduction(R)was positively correlated with the duration of leaf shedding(LS),timing of leaf shedding(TLS)and ending of leaf shedding(ELS).(3)Leaf morphological traits have a greater impact on phenology,leaf area(LA),specific leaf area(SLA)and leaf thickness(LT)are closely related to morphological traits.Species with smaller leaf area,specific leaf area and thicker leaves had earlier time of leaf emergence(TLE),late timing of leaf shedding(TLS)and ending of leaf shedding(ELS),longer duration of leaf emergence(LE),longer leaf life span(LLS)and duration of plant reproduction(R).The smaller the stem density(SD),the shorter the duration of leaf emergence(LE).Species with lower leaf nitrogen content(LNC)or higher leaf phosphorus content(LPC)have earlier leaf emergence time.Leaf nitrogen content(LNC)was negatively correlated with leaf life span(LLS)and duration of leaf emergence(LE).In summary,there are significant differences in the phenological and functional traits between shrubs and trees.Differences in phenology reduce resource competition in the temporal dimension and contribute to species coexistence and species diversity maintenance.Differences in functional traits reflect differences in resource utilization and distribution.Shrubs consume most of their substances to build defence mechanisms.Leaf life span is closely related to other phenological traits.Not only the pattern of emergence and defoliation will affect leaf life span,but also the construction and maintenance costs of genital organs are closely related to leaf life span.Leaf morphological traits had a greater impact on phenological traits,leaf area,specific leaf area,and leaf thickness were closely related to phenological traits,suggesting that plant establishment costs and defence mechanisms will affect plant leaf phenology.