Harris D, Pacovsky R S, Paul E A
Department of Plant and Soil Biology, University of California, Berkeley, CA 94720.
USDA-ARS, Western Regional Research Centre, Albany, CA 94710, USA.
New Phytol. 1985 Nov;101(3):427-440. doi: 10.1111/j.1469-8137.1985.tb02849.x.
Carbon uptake and allocation in plants that were largely dependent on microbial symbionts for N and P was compared to that in plants given inorganic fertilizer. Soybeans (Glycine max L. Merr.) were grown in sterilized soil and were either left uninoculated, or were inoculated with Rhizobium japonicum (Kirschner), or both R. japonicum and Glomus fasciculatum (Thaxter sensu Gerd.). Uninoculated plants were given N and/or P fertilizer at rates required to produce plants similar in size to inoculated plants. Carbon flows to plant parts, root nodules and vesicular-arbuscular mycorrhizas were measured in six- and nine-week-old plants by determining the distributions of C after pulse labelling with CO . Root nodules in non-mycorrhizal plants utilized 9% of total photosynthate; this was increased to 12% in nodulated, mycorrhizal plants. Mycorrhizas used 17% of the total photosynthate of six-week-old plants; this fell to 8% after nine weeks. Rates of CO fixation in leaves of nodulated or nodulated plus mycorrhizal plants were up to 52% higher than in plants without microbial symbionts. Part of the increase was due to higher specific leaf area in plants colonized by symbionts, but other factors such as source-sink relationships, starch mobilization and leaf P concentrations were also involved in the host-plant adaptations to the C demand of the microbial endophytes.
将主要依赖微生物共生体获取氮和磷的植物中的碳吸收与分配情况，与施加无机肥料的植物进行了比较。大豆（Glycine max L. Merr.）种植在灭菌土壤中，要么不接种，要么接种日本根瘤菌（Kirschner），或者同时接种日本根瘤菌和摩西管柄囊霉（Thaxter sensu Gerd.）。未接种的植物按照使植株大小与接种植物相似所需的速率施加氮和/或磷肥料。通过在以CO进行脉冲标记后测定碳的分布，来测量六周龄和九周龄植株中流向植物各部分、根瘤和丛枝菌根的碳流量。非菌根植物的根瘤利用了总光合产物的9%；在有根瘤的菌根植物中，这一比例增加到了12%。菌根利用了六周龄植株总光合产物的17%；九周后降至8%。有根瘤或有根瘤且有菌根的植株叶片中的CO固定速率比没有微生物共生体的植株高出52%。增加的部分原因是共生体定殖的植株具有更高的比叶面积，但其他因素，如源库关系、淀粉动员和叶片磷浓度，也参与了宿主植物对微生物内生菌碳需求的适应性。
