GAS-EXCHANGE CHARACTERISTICS OF POPULUS-TRICHOCARPA, POPULUS-DELTOIDES AND POPULUS-TRICHOCARPA X POPULUS-DELTOIDES CLONES
GAS-EXCHANGE CHARACTERISTICS OF POPULUS-TRICHOCARPA, POPULUS-DELTOIDES AND POPULUS-TRICHOCARPA X POPULUS-DELTOIDES CLONES
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DOI：
10.1093/treephys/8.2.145
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发表时间：
1991-03-01
期刊：
影响因子：
4
通讯作者：
ZWIER, JC
中科院分区：
文献类型：
--
作者：
BASSMAN, JH;ZWIER, JC
研究了2个大叶杨无性系净光合速率、暗呼吸速率、光呼吸速率、蒸腾速率和气孔导度对光照、温度、叶片-空气水汽密度差和水分胁迫的响应（一个来自华盛顿西部潮湿的沿海气候，一个来自华盛顿东部干燥的大陆性气候），一个美洲黑猩猩克隆，在温室生长的树木中，对于美洲黑杨、美洲黑杨×美洲黑杨和东华盛顿生态型的美洲黑杨，光合作用的光饱和发生在约800 μ mol m-2 s-1，而对于华盛顿西部生态型的大果杨，则约为600 μ mol m ~（-2）s ~（-1）。 在饱和光照和最适温度为25 ℃时，美洲黑杨、厚果×美洲黑杨、厚果东、西华盛顿无性系的平均净光合速率分别为20.7、18.8、18.2和13.4 μ mol CO2 m-2 s-1。 在所有的克隆，净光合作用下降约14%，VDD从3增加到18克H2O m-3。 气孔导度随着木质部压力势（XPP）的降低而急剧下降，除西部华盛顿无性系外。 该克隆的气孔对XPP的变化不敏感，并且不能控制水分散失。 华盛顿杨东无性系在-2.0 MPa左右气孔完全关闭（气孔导度< 0.05 cm s-1），美洲黑杨和美洲黑杨×美洲黑杨无性系在-1.25 MPa左右气孔完全关闭（气孔导度< 0.05 cm s-1）。 蒸腾速率最高的P.果× P. deltoides克隆和最低的P.果的西部华盛顿克隆。 美洲黑杨无性系和东华盛顿杨无性系的水分利用效率最高，西华盛顿杨无性系的水分利用效率最低。 结果表明：（1）东、西华盛顿无性系的气体交换特征反映了对自然环境的适应;（2）将西华盛顿系的美洲黑杨与耐旱性更强的美洲黑杨杂交，产生了更适应西北太平洋内陆气候的植株，虽然杂种的气孔对土壤水分亏缺的反应比东华盛顿无性系的保守;以及（3）将东部华盛顿黑棉白杨的克隆引入育种计划，可能会产生具有良好生长特性的品系，增强WUE和对土壤水分亏缺的适应。
Responses of net photosynthesis, dark respiration, photorespiration, transpiration, and stomatal conductance to irradiance, temperature, leaf-to-air vapor density difference (VDD), and plant water stress were examined in two Populus trichocarpa clones (one from a moist, coastal climate in western Washington and one from a dry, continental climate in eastern Washington), one P. deltoides clone, and two P. trichocarpa x P. deltoides clones.Light saturation of photosynthesis in greenhouse-grown trees occurred at about 800-mu-mol m-2 s-1 for P. deltoides, P. trichocarpa x P. deltoides, and the eastern Washington ecotype of P. trichocarpa, but at about 600-mu-mol m-2 s-1 for the western Washington ecotype of P. trichocarpa. Average net photosynthesis (at saturating irradiance and the optimum temperature of 25-degrees-C) was 20.7, 18.8, 18.2 and 13.4-mu-mol CO2 m-2 s-1 for P. deltoides, P. trichocarpa x P. deltoides, and the eastern and western Washington clones of P. trichocarpa, respectively. In all clones, net photosynthesis decreased about 14% as VDD increased from 3 to 18 g H2O m-3. Stomatal conductance decreased sharply with decreasing xylem pressure potential (XPP) in all clones except the western Washington clone of P. trichocarpa. Stomata in this clone were insensitive to changes in XPP and did not control water loss. Complete stomatal closure (stomatal conductance < 0.05 cm s-1) occurred at about -2.0 MPa in the eastern Washington clone of P. trichocarpa and around -1.25 MPa in the P. deltoides and P. trichocarpa x P. deltoides clones. Transpiration rates were highest in the P. trichocarpa x P. deltoides clone and lowest in the western Washington clone of P. trichocarpa. The P. deltoides clone and eastern Washington clone of P. trichocarpa had the highest water use efficiency (WUE) and the western Washington clone of P. trichocarpa had the lowest WUE. The hybrids were intermediate.It was concluded that: (1) gas exchange characteristics of eastern and western Washington clones of P. trichocarpa reflected adaptation to their native environment; (2) crossing the western Washington clone of P. trichocarpa with the more drought resistant P. deltoides clone produced plants better adapted to the interior Pacific Northwest climate, although the stomatal response to soil water deficits in the hybrid was conservative compared with that of the eastern Washington clone of P. trichocarpa; and (3) introducing eastern Washington clones of black cottonwood into breeding programs is likely to yield lines with favorable growth characteristics combined with enhanced WUE and adaptation to soil water deficits.