不同條件下樹木死亡的水力失衡和碳饑餓機(jī)制
發(fā)布時(shí)間：2019-05-23 14:01
【摘要】：對全球氣候變化背景下大范圍森林死亡的研究是當(dāng)前的一個(gè)熱點(diǎn)。樹木難以維持碳-水平衡被推測為樹木死亡的主要原因。本研究選擇了不同降雨水平、蟲害與樹木物候,以及不同光強(qiáng)和樹木大小等三種不同的環(huán)境條件或關(guān)系,研究水力失衡(Hydraulic failure)和碳饑餓(Carbon starvation)機(jī)制對樹木生長和存活的影響。包括探索降雨減少后四照花(Dendrobenthamia japonica(DC.)Fang var.chinensis(Osborn.)Fang)、三椏烏藥(Lindera obtusiloba Bl.Mus.Bot.)和水榆花楸(Sorbus alnifolia(Sieb.et Zucc.)K.Koch)三個(gè)不同的isohydry(等水)-anisohydry(異水)功能型植物的氣孔行為和木質(zhì)部栓塞脆弱性及其植物體內(nèi)的水-碳變化和三椏烏藥的枯死機(jī)理;研究蟲害葉損失對不同物候樹種木荷(Schima superba Gardn.et Champ.)和黃杞(Engelhardia roxburghiana,Wall.)的危害程度;以及光照強(qiáng)度和樹體大小如何影響銳齒櫟樹木的(Quercus aliena var.acuteserrata)碳-水平衡。本研究對認(rèn)識和預(yù)測全球變化背景下森林結(jié)構(gòu)變化和演替具有重要的理論意義。主要結(jié)論如下:1、對于寶天曼共生的四照花、三椏烏藥、水榆花楸這三個(gè)樹種,試驗(yàn)結(jié)果表明在isohydry(等水)-anisohydry(異水)功能型植物譜中,四照花在isohydry這一端,水榆花楸在anisohydry這一端,而三椏烏藥在兩者之間。在截雨處理后四照花氣孔易關(guān)閉而保水,導(dǎo)致其水勢在三個(gè)樹種中最高,但凈光合速率和非結(jié)構(gòu)性碳(NSC)降低。而水榆花楸在截雨處理后氣孔易維持開放但失水,水勢在三個(gè)樹種中最低,但對氣體交換的限制低,在三個(gè)樹種中最易出現(xiàn)NSC的盈余。即偏anisohydric的水榆花楸相比偏isohydric的四照花中午水勢更負(fù),但NSC的積累受到的影響較小。2、經(jīng)人工截雨處理后,具有偏anisohydric策略的水榆花楸和具有偏isohydric策略的四照花都相對適應(yīng)了降低的水分環(huán)境,但在氣孔行為策略上介于二者之間的三椏烏藥因水力失衡而嚴(yán)重枯死。除氣孔反應(yīng)類型之外,木質(zhì)部栓塞脆弱性在樹木應(yīng)對干旱中也扮演重要的角色。三個(gè)樹種中,三椏烏藥栓塞脆弱性最大,亦即抗栓塞能力最低,截雨后出現(xiàn)水力失衡,導(dǎo)致頂端枯死。該研究證明水力失衡不僅取決于氣孔反應(yīng)類型,還受木質(zhì)部栓塞脆弱性的制約。3、鼎湖山的季節(jié)性干旱沒有和蟲害產(chǎn)生交互作用,而是換葉物候的不同節(jié)律造成的碳儲備降低導(dǎo)致蟲害對木荷和黃杞的危害程度不同。鼎湖山的常綠闊葉樹種木荷在二月份換葉,換葉過程本身消耗了大量的NSC。而另一個(gè)冠層樹種黃杞的換葉時(shí)間在五月。鼎湖山蟲害爆發(fā)是在3-4月,剛好在木荷換葉之后,黃杞換葉之前�；诖髽淠贻喌姆治鲲@示在蟲害(T.quadraria)爆發(fā)年份木荷橫向生長降低,而黃杞?jīng)]有受到抑制。用小樹模擬蟲害的去葉試驗(yàn)顯示:去葉處理顯著降低了木荷葉片和枝條的生長,限制了去葉處理后木荷的光合固碳量,阻礙了其根部和木質(zhì)部NSC的恢復(fù),從而導(dǎo)致了木荷高的死亡率。雖然葉損失也降低了黃杞葉片和枝條的生長,但其降低幅度遠(yuǎn)小于木荷。在去葉處理10個(gè)月之后,黃杞恢復(fù)了NSC儲備,沒有出現(xiàn)樹木死亡。因此,NSC儲備和蟲害對樹木的危害程度密切相關(guān)。當(dāng)把物候循環(huán)考慮進(jìn)來的時(shí)候,容易解釋蟲害葉損失對木荷生長、NSC儲備和存活的影響大于黃杞。對水分關(guān)系的研究表明鼎湖山的季節(jié)性干旱沒有對兩個(gè)樹種造成損害。4、以銳齒櫟大樹冠層上部、樹冠下部、林下小樹和林窗小樹四個(gè)材料為研究對象。大樹冠層上部存在明顯的水力限制,導(dǎo)致了大樹冠層上部的凈光合速率、氣孔導(dǎo)度都顯著低于光有效性相同的林窗小樹。由于樹冠頂部經(jīng)常受到水分脅迫及由此帶來的生長下降,使得大樹冠層上部葉片和韌皮部的NSC相對積累,而經(jīng)常性的栓塞修復(fù)消耗了木質(zhì)部大量的NSC。光有效性高的大樹冠層上部和林窗小樹葉片的光合能力顯著大于光有效性低的冠層下部和林下小樹;大樹冠層下部的光合能力也大于林下小樹。綜合考慮不同樹木大小和受光程度,光照因素對銳齒櫟光合作用的塑造起更主要作用。5、寶天曼銳齒櫟林下光照強(qiáng)度遠(yuǎn)低于林外。林下低光環(huán)境顯著限制了銳齒櫟幼樹的光合潛能及固碳,其NSC濃度顯著低于大樹和林窗小樹;林下銳齒櫟幼樹的這種NSC狀態(tài)很容易因碳饑餓而死亡。另外,盆栽遮陰試驗(yàn)表明遮陰處理顯著降低了銳齒櫟幼苗的干物質(zhì)量和NSC濃度。模擬光斑處理顯著提高了遮陰幼苗在高光強(qiáng)下的光合潛能,且模擬光斑使得幼苗NSC濃度顯著高于一直遮陰處理的幼苗,緩解了遮陰對幼苗碳儲備的不利影響,所以高密度的光斑對維持寶天曼銳齒櫟林下銳齒櫟幼苗凈的碳平衡可能有一定的作用。
[Abstract]:The research of large-scale forest death in the context of global climate change is a hot spot in the world. It is difficult for trees to maintain carbon-water balance as the main cause of tree death. In this study, three different environmental conditions or relationships, such as different rainfall levels, pest and tree phenology, and different light intensity and tree size, were selected to study the effects of hydro-imbalance and carbon starvation on the growth and survival of trees. It includes the following steps: to explore the four-shot flowers (Dendrotenham japonica (DC.) Tang var. chinensis (Osborn.) Tang) and three-(Lindera obtusiloba Bl. Mus. Bot) after the reduction of rainfall. ) And Sorbus alngifolia (Sieb.et Zucc). ) K. Koch) The stomatal behavior of three different isohydryry (isowater)-anishanyry (isowater) functional plant and the water-carbon change of the xylem and the mechanism of the dead-death of the water-carbon in the plant, and the mechanism of the dead-death of the triamcinolone; and the study of the loss of the insect-leaf to the Schima superba Gardn.et. ) And Engelhardia roxburghiana, Wall. ) The degree of harm; and how the light intensity and the size of the tree affect the carbon-water balance of Quercus aliena var. acuta. This study is of great theoretical significance for understanding and predicting the change and succession of forest structure in the context of global change. The main conclusions are as follows:1. The experimental results show that in the plant spectrum of isowater, the four-way flower is in the one end of isohydary, and the water elm is in the one end of anisoheyry. And three of them are in the middle of the two. The water potential was the highest in the three tree species, but the net photosynthetic rate and non-structural carbon (NSC) decreased. However, the water loss and water potential are the lowest among the three tree species, but the limitation of gas exchange is low, and the surplus of the NSC is the most common among the three tree species. I. e., the water potential of the anisoheyric water elm is more negative than the water potential at noon, but the effect of the accumulation of the nsc is less. But in the air-hole behavior strategy, the three-drug-black drug between the two is severely dead due to the hydraulic imbalance. In addition to that type of pore reaction, the vulnerability of xylem embolism play an important role in the response of trees to drought. Among the three tree species, the most of the three kinds of Wuyao embolization is the lowest, that is, the anti-embolism ability is the lowest, and the hydraulic imbalance occurs after the cut-off, leading to the dead end of the top. The study shows that the hydraulic imbalance depends not only on the type of pore reaction but also by the vulnerability of the xylem.3. The seasonal drought of the Dinghushan Mountain has no interaction with the insect. But the reduction of the carbon stock caused by the different rhythm of the change of the phenology leads to a different degree of damage to the wood and the yellow soil by the insect. The evergreen broad-leaved tree of Dinghushan is changed in February, and the leaf-changing process itself consumes a great deal of NSC. And the leaf-change time of the other canopy tree was in May. Dinghushan insect outbreaks were in March-April, just after the change of the leaves of the wood, before the change of the leaves. Based on the analysis of the tree-year round, the lateral growth of the wood-to-load was reduced in the year of the outbreak of the pest (T. quadia), while the yellow rice was not inhibited. The leaf-defoliation test showed that the leaf-defoliation treatment significantly reduced the growth of the leaves and branches of the leaves, and restricted the photosynthesis and fixation of the wood-loaded leaves after the defoliation treatment, which hindered the restoration of the root and the xylem NSC, thus resulting in a high mortality rate. Although leaf loss also reduces the growth of the leaves and branches of the yellow leaves, it reduces the amplitude much less than that of the wood. After 10 months of defoliation, the NSC reserve was restored and no tree death was present. Therefore, the NSC reserves and pests are closely related to the degree of damage to the trees. When the phenological cycle is taken into account, it is easy to explain the effect of the loss of the pest leaf on the growth of the wood, the reserve and the survival of the NSC. The research on the relation between the water and water shows that the seasonal drought of the Dinghushan Mountain has no damage to the two tree species.4. The four materials of the upper part of the large crown layer of the sharp-toothed oak, the lower part of the crown, the lower and the lower trees of the forest and the small tree of the forest window are the research objects. There is a significant hydraulic restriction on the upper part of the large crown layer, which results in the net photosynthetic rate at the upper part of the large crown layer, and the air hole conductivity is significantly lower than that of the forest window with the same light efficiency. Since the top of the crown is often subjected to water stress and the resulting decline in growth, the NSCs of the upper and the bast parts of the large crown layer are relatively accumulated, while the recurrent plug repair consumes a large number of the NSCs of the xylem. And the photosynthetic capacity of the lower part of the large crown layer is larger than that of the lower tree. Considering the size and the light-receiving degree of different trees, the light factors play a more important role in shaping the photosynthesis of the Quercus acuminata. The low light environment in the forest significantly limits the photosynthetic potential and the solid carbon of the young trees of the sharp-tooth oak, and the concentration of the NSC is lower than that of the tree and the forest window. The NSC state of the young trees of the Quercus acumen is very easy to die due to carbon starvation. In addition, the pot-shading test indicated that the shade treatment significantly reduced the dry matter quality and the NSC concentration of the sharp-tooth oak seedlings. the simulated light spot treatment obviously improves the photosynthetic potential of the shade seedling under the high light intensity, and the simulated light spot is that the concentration of the seedling NSC is obviously higher than that of the seedling which has been subjected to the shade treatment, and the adverse effect of the shading on the carbon storage of the seedling is relieved, So the high-density light spot can play a certain role in maintaining the net carbon balance of the Quercus acutissima seedlings under the Baotianman sharp-tooth oak forest.
【學(xué)位授予單位】：中國林業(yè)科學(xué)研究院
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S718.4
，
本文編號：2483957
[Abstract]:The research of large-scale forest death in the context of global climate change is a hot spot in the world. It is difficult for trees to maintain carbon-water balance as the main cause of tree death. In this study, three different environmental conditions or relationships, such as different rainfall levels, pest and tree phenology, and different light intensity and tree size, were selected to study the effects of hydro-imbalance and carbon starvation on the growth and survival of trees. It includes the following steps: to explore the four-shot flowers (Dendrotenham japonica (DC.) Tang var. chinensis (Osborn.) Tang) and three-(Lindera obtusiloba Bl. Mus. Bot) after the reduction of rainfall. ) And Sorbus alngifolia (Sieb.et Zucc). ) K. Koch) The stomatal behavior of three different isohydryry (isowater)-anishanyry (isowater) functional plant and the water-carbon change of the xylem and the mechanism of the dead-death of the water-carbon in the plant, and the mechanism of the dead-death of the triamcinolone; and the study of the loss of the insect-leaf to the Schima superba Gardn.et. ) And Engelhardia roxburghiana, Wall. ) The degree of harm; and how the light intensity and the size of the tree affect the carbon-water balance of Quercus aliena var. acuta. This study is of great theoretical significance for understanding and predicting the change and succession of forest structure in the context of global change. The main conclusions are as follows:1. The experimental results show that in the plant spectrum of isowater, the four-way flower is in the one end of isohydary, and the water elm is in the one end of anisoheyry. And three of them are in the middle of the two. The water potential was the highest in the three tree species, but the net photosynthetic rate and non-structural carbon (NSC) decreased. However, the water loss and water potential are the lowest among the three tree species, but the limitation of gas exchange is low, and the surplus of the NSC is the most common among the three tree species. I. e., the water potential of the anisoheyric water elm is more negative than the water potential at noon, but the effect of the accumulation of the nsc is less. But in the air-hole behavior strategy, the three-drug-black drug between the two is severely dead due to the hydraulic imbalance. In addition to that type of pore reaction, the vulnerability of xylem embolism play an important role in the response of trees to drought. Among the three tree species, the most of the three kinds of Wuyao embolization is the lowest, that is, the anti-embolism ability is the lowest, and the hydraulic imbalance occurs after the cut-off, leading to the dead end of the top. The study shows that the hydraulic imbalance depends not only on the type of pore reaction but also by the vulnerability of the xylem.3. The seasonal drought of the Dinghushan Mountain has no interaction with the insect. But the reduction of the carbon stock caused by the different rhythm of the change of the phenology leads to a different degree of damage to the wood and the yellow soil by the insect. The evergreen broad-leaved tree of Dinghushan is changed in February, and the leaf-changing process itself consumes a great deal of NSC. And the leaf-change time of the other canopy tree was in May. Dinghushan insect outbreaks were in March-April, just after the change of the leaves of the wood, before the change of the leaves. Based on the analysis of the tree-year round, the lateral growth of the wood-to-load was reduced in the year of the outbreak of the pest (T. quadia), while the yellow rice was not inhibited. The leaf-defoliation test showed that the leaf-defoliation treatment significantly reduced the growth of the leaves and branches of the leaves, and restricted the photosynthesis and fixation of the wood-loaded leaves after the defoliation treatment, which hindered the restoration of the root and the xylem NSC, thus resulting in a high mortality rate. Although leaf loss also reduces the growth of the leaves and branches of the yellow leaves, it reduces the amplitude much less than that of the wood. After 10 months of defoliation, the NSC reserve was restored and no tree death was present. Therefore, the NSC reserves and pests are closely related to the degree of damage to the trees. When the phenological cycle is taken into account, it is easy to explain the effect of the loss of the pest leaf on the growth of the wood, the reserve and the survival of the NSC. The research on the relation between the water and water shows that the seasonal drought of the Dinghushan Mountain has no damage to the two tree species.4. The four materials of the upper part of the large crown layer of the sharp-toothed oak, the lower part of the crown, the lower and the lower trees of the forest and the small tree of the forest window are the research objects. There is a significant hydraulic restriction on the upper part of the large crown layer, which results in the net photosynthetic rate at the upper part of the large crown layer, and the air hole conductivity is significantly lower than that of the forest window with the same light efficiency. Since the top of the crown is often subjected to water stress and the resulting decline in growth, the NSCs of the upper and the bast parts of the large crown layer are relatively accumulated, while the recurrent plug repair consumes a large number of the NSCs of the xylem. And the photosynthetic capacity of the lower part of the large crown layer is larger than that of the lower tree. Considering the size and the light-receiving degree of different trees, the light factors play a more important role in shaping the photosynthesis of the Quercus acuminata. The low light environment in the forest significantly limits the photosynthetic potential and the solid carbon of the young trees of the sharp-tooth oak, and the concentration of the NSC is lower than that of the tree and the forest window. The NSC state of the young trees of the Quercus acumen is very easy to die due to carbon starvation. In addition, the pot-shading test indicated that the shade treatment significantly reduced the dry matter quality and the NSC concentration of the sharp-tooth oak seedlings. the simulated light spot treatment obviously improves the photosynthetic potential of the shade seedling under the high light intensity, and the simulated light spot is that the concentration of the seedling NSC is obviously higher than that of the seedling which has been subjected to the shade treatment, and the adverse effect of the shading on the carbon storage of the seedling is relieved, So the high-density light spot can play a certain role in maintaining the net carbon balance of the Quercus acutissima seedlings under the Baotianman sharp-tooth oak forest.
【學(xué)位授予單位】：中國林業(yè)科學(xué)研究院
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S718.4
，
本文編號：2483957
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