Responses Of Leaf Characters Of Masson Pine To Altitude Gradient

Currently coexistence mechanisms driving the same generic plants in the regional scale is still an important ecology issue. With the development of system functions ecology,the study on the functional traits differentiation of related species along environmental gradient may provide evidence for explaining the coexistence of species with similar affinity on the community scale. We analyze thirty-two leaf traits included physiological ecological characteristics,morphological traits and nutrient content change in P. taiwanensis and P. massoniana along an altitudinal gradient in Daiyun Mountain,to explore how leaf traits change along the elevation gradient in the regional scale.Then analysised the influence of environmental factors on leaf traits and compared the response pattern and adaptation strategies.(1)There were different patterns of antioxidant system response to the altitudinal gradient in P. taiwanensis and with elevation increasing,coniferous malondialdehyde(MDA) content increased first and then decreased in P. Taiwanensis at south and north slope,malondialdehyde(MDA) content increased first and then decreased in P. Massoniana at southern slope,while decreased first and then increased at northern slope.Peroxidase(POD) and catalase(CAT) content increased fitst and then decreased,increased again at high altitude,while superoxide dismutase increased first and decreased then in P. taiwanensi.POD、CAT、SOD content decreased first and then increased basically in P. Taiwanensis at northern slope. Showed that there were diferent modes of response to diferent slpoe in P. taiwanensis.With altitude increasing,POD、CAT、SOD content showed an upward trend,while increasing altitude close to the upper limit of Masson pine distribution,CAT and POD declined in P. Massoniana at southern slope.CAT and POD content showed an decline trend,SOD showed no significant changes in Masson pine at northern slope.(2)There were diferent photosynthetic patterns of response to altitude in two species:hlorophyll a(Chla), chlorophyll b(Chlb), chlorophyll (a+b)(Chl (a+b)) content showed a declne after an upper trend in P. Taiwanensis at northern-southern slope,chla/b had no significant trend with altitude increasing; Chla、Chlb、Chl(a+b) content basically showed a up-down-up trend at altitude of southern slope,while Chla、Chlb、Chl(a+b) content decreased first and then increased in P. Massoniana at altitude of northern slope.Chl(a/b) content showed no significant variation,Chl(a/b) content showed a decline trend in P. Massoniana at altitude of northern slope.(3)Specific leaf area of P. Taiwanensis showed a decline trend at high-altitude of both slope, coniferous dry matter content increased at the northern slope.Both Specific leaf area and coniferous dry matter showed no significant changes in P. Massoniana at altitude of Southern slope,only leaf area and leaf length showed significant change,which indicated morphological changes in Needles of P. Massoniana at southern slope keep a constant an tend with elevation increasing.Morphological changes in Needles of P. Taiwanensis varied obviously with altitude changes:coniferous area,coniferous length and coniferous dry weight had diferent degrees of decline.(4)The mean overall phosphorus content in two species is below the national average, indicating the phosphoru content in two species are strongly restricted supply in the growth process.The elevation of each southern slope, N elements content in leaves were significantly lower than P. massoniana,C:N, C:P in P. Massoniana were significantly lower than P.taiwanensis at the same altitude. Potassium, calcium, content in P.taiwanensis were significantly higher than that of P. Massoniana. This showed there were different resource allocation and utilization strategies between the two plants in elevation gradient.(5)The soluble sugar,starch,flavonoid and proline content in leaves of two species increased with increasing altitude at the same altitude gradient of northern and southern slope.The soluble sugar, content of P. Massoniana in southern slope were higher than leaves of P.taiwanensis at the same elevation gradient. The starch content in leaves of P. Massoniana were higher than leaves of P.taiwanensis at the same elevation gradients. This showed there were some ability to adapt changing environmental gradients, but the adaptability of two species in the same environment were different.(6)Plasticity analysis of antioxidants, chlorophyll content, leaf morphology, stoichiometry features in P. taiwanensis and P. Massoniana showed that composite plasticity index in descending order: antioxidants, chlorophyll content, leaf morphology, stoichiometry features. This indicated that Description with elevation, antioxidants, chlorophyll play a important role in adapting environment, leaf morphology and stoichiometry features such as the role is relatively small.(7)The biplot of Redundancy analysis revealed relationship between leaf traits of P. taiwanensis and P. Massoniana and environmental factors.Altitude variation have a higher impact on the leaf traits vriation in two species,leaf traits were affected by soil factors.There was a close relationship between leaf traits.In summary, Morphological characteristics, nutrient content, antioxidant system and resilience substances, changes of photosynthetic pigments associated with changes in elevation, and there were different modes of response to environmental gradients.