Plant Water Potentials and Plant Physiology at the Sevilleta National Wildlife Refuge, New Mexico (1989-1992)

Physiological status of plants is monitored in conjunction with the sampling schedule outlined in Sevilleta Plant Demography. Several perennial life forms, including tree (Juniperus and Pinus), shrub (Larrea) and grass (Oryzopsis and Sporobolus), are being monitored at 1-3 of four sites which differ in elevation and topography as well as edaphic and annual precipitation characteristics. For the 1990 field season we are adding a spring annual, Lesquerella to our sampling efforts at these same sites. Currently, water status (xylem potentials, bars) is monitored twice a year, in spring (after the 'dry' season) and fall (after the 'wet' season). Three replicate measurements are made on each of 10-20 individuals per species per site. Three measurements are made at pre-dawn and midday to determine the diurnal range of values for each plant. For the 1990 field season, we will also be measuring peak photosynthetic rates for selected individuals by gas exchange measurements and porometry. Together with demographic data, this data set permits assessment of the physiological bases of plant growth and reproduction in response to short- and long-term changes in abiotic and biotic aspects of the environment.

本数据集结合《塞维利塔植物种群统计学》（Sevilleta Plant Demography）所拟定的采样方案，开展植物生理状态监测工作。监测对象涵盖多种多年生植物生活型，包括乔木（刺柏属Juniperus、松属Pinus）、灌木（拉瑞阿属Larrea）与草本（稻定草属Oryzopsis、鼠尾粟属Sporobolus），在4个海拔、地形、土壤特性及年降水特征均存在差异的样地中，选取其中1-3个样地开展监测。1990年野外季期间，我们还将在上述样地中新增对春季一年生植物Lesquerella的采样工作。目前，我们每年开展两次水分状态监测，分别于春季（‘旱季’结束后）与秋季（‘雨季’结束后）进行，测定指标包括木质部水势（xylem potentials），单位为巴（bars）。每个样地内的每一物种，选取10-20株个体，每株开展三次重复测量；并分别在黎明前与正午各进行三次测定，以获取单株植物的生理指标日变化范围。1990年野外季，我们还将通过气体交换法与气孔计法，对选定植株的光合峰值速率进行测定。结合种群统计数据，本数据集可用于评估植物生长与繁殖的生理基础，以响应环境中非生物与生物因子的短期及长期变化。