Grulke N E, Preisler H K, Rose C, Kirsch J, Balduman L
USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA.
USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
New Phytol. 2002 Jun;154(3):621-631. doi: 10.1046/j.1469-8137.2002.00403.x.
• The effect of O exposure or uptake on carbon acquisition (net assimilation (A) or gross photosynthesis (P )), with and without drought stress, is reported here in 40-yr-old-ponderosa pine (Pinus ponderosa) trees. • Maximum daily gas exchange was measured monthly for 12 trees at four sites differing in pollutant exposure over two growing seasons with above- and below-average annual precipitation. Gas exchange measures were estimated between sampling periods using a generalized additive regression model. • Both A and P generally declined with cumulative O exposure or uptake at all sites. As a response variable, P was slightly more sensitive than A to cumulative O exposure. As a metric, O uptake vs exposure permitted slightly better statistical resolution of seasonal response between sites. • The effect of late summer drought stress was statistically significant only at the moderate pollution site, and combined synergistically with O exposure or uptake to reduce P . The general additive model allows the user to define a deleterious level of cumulative O exposure or uptake, and to quantitatively assess biological response.
• 本文报告了40年生的美国黄松（Pinus ponderosa）树木在有和没有干旱胁迫的情况下，臭氧暴露或吸收对碳获取（净同化率（A）或总光合作用（P）） 的影响。
• 在两个生长季节中，每月对四个污染物暴露程度不同的地点的12棵树测量最大日气体交换量，这些地点的年降水量有高于平均水平和低于平均水平之分。在采样期之间，使用广义相加回归模型估计气体交换量。
• 在所有地点，A和P通常都随着累积臭氧暴露或吸收而下降。作为响应变量，P对累积臭氧暴露的敏感性略高于A。作为一种度量标准，臭氧吸收与暴露相比，能在各地点之间对季节性响应实现稍好的统计分辨率。
• 夏末干旱胁迫的影响仅在中度污染地点具有统计学意义，并且与臭氧暴露或吸收协同作用，降低了P。广义相加模型允许用户定义累积臭氧暴露或吸收的有害水平，并定量评估生物响应。
