Hydraulic architecture and vulnerability to drought-induced embolism in southern boreal tree species of Inner Asia
Hydraulic architecture and vulnerability to drought-induced embolism in southern boreal tree species of Inner Asia
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DOI：
10.1093/treephys/tpy116
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发表时间：
2019-03-01
期刊：
影响因子：
4
通讯作者：
Hauck, Markus
中科院分区：
文献类型：
--
作者：
Dulamsuren, Choimaa;Abilova, Sholpan B.;Hauck, Markus
对6种重要的中亚南部北方阔叶林树种的树枝木质部的木材解剖和水力特性进行了研究，以便从树种的抗栓性、潜在的导水率、平均导管直径和导管密度来推断树种的抗旱性。唯一被研究的被子植物桦树比所有五种针叶树(常绿或夏绿)对空化的敏感性要高得多，即使在桦树中使用88%的电导率损失(P-88)，但在针叶树中使用50%(P-50)作为临界阈值。这表明，在人为干扰(如伐木、人为火灾)后，已广泛取代针叶林的先锋白桦林比原始针叶林更容易受到气候变暖引发的干旱的影响。与预期相反的是，普遍较干旱暴露的轻度针叶松(Larix siberica Ledeb.，Pinus cervestris L.)其P-50和P-88值并不总是低于暗针叶油松，这表明其他干旱生存性状也同样重要。在暗针茅树种中，只有西伯利亚松树，而没有西伯利亚冷杉。和倒卵云杉的P-50值相对较高，表明其易损性较高。在浅色针阔混交林中，西伯利亚马尾松的抗栓性低于马尾松。面对内亚地区快速的气候变暖和干旱，南方北方树种的干旱生存策略值得进一步深入研究，其中应该包括其他干旱生存特征。
The branch xylem of six important Inner Asian southern boreal forest trees was studied for wood-anatomical and hydraulic traits in order to infer the species' drought tolerance from embolism resistance, potential hydraulic conductivity, mean conduit diameters and conduit density. The only studied angiosperm tree, Betula pendula Roth, was much more sensitive to cavitation than all five conifers (evergreen or summer-green), even when using 88% loss of conductivity (P-88) in birch, but 50% (P-50) in the conifers as critical thresholds. This suggests that pioneer birch forests, which have widely replaced the conifer climax forests after anthropogenic disturbance (e.g., logging, man-made fire), are more vulnerable to climate warming-induced drought than the original conifer forests. In contrast to expectation, the generally more drought-exposed light taiga species (Larix sibirica Ledeb., Pinus sylvestris L.) did not have consistently lower P-50 and P-88 values than the dark taiga conifers, suggesting that other drought survival traits are equally important. Among the dark-taiga species, only Pinus sibirica Du Tour, but not Abies sibirica Ledeb. and Picea obovata Ledeb., had relatively high P-50 values indicating higher vulnerability. In the light-taiga forest, P. sylvestris revealed lower embolism resistance than L. sibirica. In the face of rapid climate warming and drying in Inner Asia, the drought survival strategies of southern boreal tree species deserve further intensive study, which should include other drought survival traits.