EFFECTS OF CO2 AND TEMPERATURE ON GROWTH AND RESOURCE USE OF COOCCURRING C3 AND C4 ANNUALS
EFFECTS OF CO2 AND TEMPERATURE ON GROWTH AND RESOURCE USE OF COOCCURRING C3 AND C4 ANNUALS
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DOI：
10.2307/1940673
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发表时间：
1992-08-01
期刊：
影响因子：
4.8
通讯作者：
BAZZAZ, FA
中科院分区：
文献类型：
--
作者：
COLEMAN, JS;BAZZAZ, FA
我们研究了CO2浓度和温度如何相互作用，影响生长，资源获取和资源分配的两个一年生植物，提供了一个单一的脉冲的营养。对生长在大气CO_2浓度为400或700-穆尔/L、光照/黑暗温度为28-degree/22-degree或38-degree/31-degree-C的环境中的Abutilon theophrasti（C3）和Amaranthus retroflexus（C4）的个体进行生理和生长测量。CO2和温度升高处理对植物生长、资源分配和资源获取具有显著的独立和交互作用（即，光合作用和氮吸收），这些影响的强度和方向往往取决于植物物种。例如，苋属植物的最终生物量在28度时因CO2升高而增加，但在38度时则受到抑制。对于Abutilon，CO2浓度升高增加了初始植物的相对生长速率在28度，但不是在38度，并没有显着的影响，最终生物量在任一temperature.These结果解释光的CO2和温度的交互作用对净叶面积生产和损失率，净全株氮的保留。在28摄氏度，CO2浓度升高刺激了这两个物种的叶面积的初始生产，这导致了在较高的CO2水平的生物量积累的初始刺激。然而，在28度的CO2浓度升高时，Abutilon的净叶面积损失率增加，而Amaranthus的净叶面积损失率下降。此外，高CO2浓度明显提高了苋在此温度下的氮保持能力，这可能有助于提高光合作用，而在Abutilon氮保持不受影响。因此，在28度，最终的生物量的<$伦没有刺激在高CO2的环境，而最终的生物量的苋。在38度下，与环境CO2生长的植物相比，在CO2升高的情况下，Abutilon的峰值叶面积略有减少，但在实验早期，每单位叶面积的光合作用速率增加，显然弥补了叶面积的减少。对于苋在38度，峰值叶面积生产不受CO2处理的影响，但净叶面积损失率加快CO2浓度升高的条件下，伴随着全株氮含量和叶片光合作用的大幅减少。这可能导致减少生物量积累的高CO2生长的植物，我们观察到在过去30 d的growth.Plants生长在CO2浓度升高的两个物种表现出减少的组织特异性氮吸收率，增加植物光合速率每单位的电导，并增加初始分配的生物量根，无论温度。这两个物种的植物生长在一个升高的温度制度下，大大降低了生殖分配，增加分配茎生物量，并增加植物水通量在两个CO2处理。植物的年龄也影响了我们对植物对CO2和温度处理的反应的解释。例如，CO2处理对生长的<$otilon的显着影响是明显的早期，开始开花之前，当氮的可用性将是最高的，盆空间不会受到限制。然而，相反是真实的苋，其中CO2处理对植物生长的显着影响是不可检测的，直到最后30 d的experiment.Elevated CO2与温度的相互作用，以不同的方式影响植物生产力比已经预测从植物对CO2浓度升高的反应。此外，大多数的CO2浓度和温度对植物生长的相互作用的影响，可以解释在光的净叶面积生产和损失，氮保留率，并在较小程度上，光合作用和资源分配的影响。
We examined how CO2 concentrations and temperature interacted to affect growth, resource acquisition, and resource allocation of two annual plants that were supplied with a single pulse of nutrients. Physiological and growth measurements were made on individuals of Abutilon theophrasti (C3) and Amaranthus retroflexus (C4) grown in environments with atmospheric CO2 levels of 400 or 700-muL/L and with light/dark temperatures of 28-degrees/22-degrees or 38-degrees/31-degrees-C. Elevated CO2 and temperature treatments had significant independent and interactive effects on plant growth, resource allocation, and resource acquisition (i.e., photosynthesis and nitrogen uptake), and the strength and direction of these effects were often dependent on plant species. For example, final biomass of Amaranthus was enhanced by elevated CO2 at 28-degrees but was depressed at 38-degrees. For Abutilon, elevated CO2 increased initial plant relative growth rates at 28-degrees but not at 38-degrees, and had no significant effects on final biomass at either temperature.These results are interpreted in light of the interactive effects of CO2 and temperature on the rates of net leaf area production and loss, and on net whole-plant nitrogen retention. At 28-degrees-C, elevated CO2 stimulated the initial production of leaf area in both species, which led to an initial stimulation of biomass accumulation at the higher CO2 level. However, in elevated CO2 at 28-degrees, the rate of net leaf area loss for Abutilon increased while that of Amaranthus decreased. Furthermore, high CO2 apparently enhanced the ability of Amaranthus to retain nitrogen at this temperature, which may have helped to enhance photosynthesis, whereas nitrogen retention was unaffected in Abutilon. Thus, at 28-degrees, final biomass of Abutilon was not stimulated in a high CO2 environment whereas the final biomass of Amaranthus was. At 38-degrees, Abutilon had slightly reduced peak leaf areas under elevated CO2 in comparison to ambient CO2 grown plants, but increased rates of photosynthesis per unit leaf area early in the experiment apparently compensated for reduced leaf area. For Amaranthus at 38-degrees, peak leaf area production was not affected by CO2 treatment, but the rate of net leaf area loss hastened under elevated CO2 conditions and was accompanied by substantial reductions of whole-plant nitrogen content and leaf photosynthesis. This may have led to the reduced biomass accumulation of high CO2 grown plants that we observed during the last 30 d of growth.Plants of both species grown in elevated CO2 exhibited reduced tissue-specific rates of nitrogen absorption, increased plant photosynthetic rate per unit of conductance, and increased initial allocation of biomass to roots, irrespective of temperature. Plants of both species grown under an elevated temperature regime had substantially decreased reproductive allocation, increased allocation to stem biomass, and increased plant water flux at both CO2 treatments. The age of plants also affected our interpretations of plant responses to CO2 and temperature treatments. For example, significant effects of CO2 treatment on the growth of Abutilon were evident early, prior to the initiation of flowering, when nitrogen availability would have been highest and pot space would not have been limited. Nevertheless, the opposite was true for Amaranthus, in which significant effects of CO2 treatment on plant growth were not detectable until the final 30 d of the experiment.Elevated CO2 interacted with temperature to affect plant productivity in different ways than would have been predicted from plant responses to elevated CO2 alone. Furthermore, a majority of the interactive effects of CO2 concentration and temperature on plant growth could be interpreted in light of their effects on the rates of net leaf area production and loss, nitrogen retention, and, to a lesser degree, photosynthesis and resource partitioning.