| Currently, ecological adaptability study of species in arid and semi-arid regions become one of the research hot spots of ecology. Also, plant adapt to drought environment is mainly manifested in the morphological characteristics of leaves. In this paper, the plants in Alashan Desert were taken as as the object. By measuring the following10leaf traits:leaf water content(LWC), leaf volume(LV), dry leaf density(DLD), fresh leaf density(FLD), leaf number(LN), total nitrogen content(TN), total phosphorus content(TP), nitrogen and phosphorus ratio(TN/TP), net photosynthesis rate(Pn) and photosynthetic pigment content(Cpp), we revealed the leaf traits and correlation on species and group level. The applicability of each leaf trait in different plant groups were analysised, in order to expound the ecological adaptability of desert plants. This study will provide certain theory significance and application value to reveal ecological adaptation approach of desert plants and biodiversity protection in desert regions. The main results are as follows:1. The range of LWC, LV, DLD, FLD, LN, TN, TP, TN/TP, Pn and Cpp of desert plants at the species level in turns are42.88～91.00%,2.236～16.918mL·g-1,0.060～0.472g·cm-3,0.490～0.937g·cm-3,31～5531leaf·g-1,14.918～35.401mg·g-1,1.087～3.060mg·g-1,7.967～21.915,0.037～0.224μmol·g·s-1 and7.889～34.285mg·g-1.2. According to lifeform and leaf texture,14desert plants has been divided into the following4groups:evergreen non-succulent shrubs, deciduous non-succulent shrubs and subshrubs, Deciduous succulent shrubs and subshrubs and annual succulent grasses. Among evergreen non-succulent shrubs, LV, LN and Pn are the minimum, but DLD, FLD and TN are the maximum; among deciduous non-succulent shrubs and subshrubs, LWC and FLD are the minimum, but LN and Cpp are the maximum; among deciduous succulent shrubs and subshrubs, TN, TP and Cpp are the minimum, but TN/TP is the maximum; among annual succulent grasses, DLD and TN/TP are the minimum, but LWC, LV, TP and Pn are the maximum. These described that each plant groups have their own characteristics.3. The leaves can be distinguished from succulent and non-succulent by the ratio of LWC and LV which can also reflect the succulent level of succulent leaves. The ratio of non-succulent species is about0.1, while the ratio of succulent species is above0.4. The succulent level of succulent leaves perform that Zygophyllum xanthoxylon> Halogeton glomeratus> Nitraria sibirica> Nitraria sphaerocarpa> Zygophyllum loczyi> Nitraria tangutorum> Lycium ruthenicum> Salsola passerina>Reaumuria soongarica.4. LN, TN, TP and TN/TP can reflect the leaf trait characteristics of desert plants on species level reasonably, which are good traits for characterise desert plant traits. LWC, LV, DLD, Pn and Cpp can reflect the leaf trait characteristics of succulent plants on species level more reasonably, as well as it has more applicability to succulent plants. FLD can’t reflect the leaf trait characteristics of desert plants on species level reasonably, as well as it has little applicability to desert plants. Among which, DLD and LV can reflect photosynthetic capacity and water status reasonably instead of leaf mass per area(LMA)/leaf specific mass(LSM) and specific leaf area(SLA). Also, they are more easy to measure than LMA/LSM and SLA.5. The average of TN in desert plants is25.136mg·g-1, it is higher than the average of loess plateau plants and Chinese desert plants, it is lower than the average of Chinese steppe plants, but it is much higher than the average of global plants. The average of TP in desert plants is1.865mg·g-1, it is higher than the average of loess plateau plants, the average of Chinese desert plants and the average of Chinese steppe plants, also it is higher than the average of global plants. The average of TN/TP in desert plants is14.870, it is lower than the average of loess plateau plants, the average of Chinese desert plants and the average of Chinese steppe plants, but it is more higher than the average of global plants. |
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