ROLE FOR THE PHOTOSYNTHATE DEMAND OF ECTOMYCORRHIZAS IN THE RESPONSE OF DOUGLAS-FIR SEEDLINGS TO DRYING SOIL
ROLE FOR THE PHOTOSYNTHATE DEMAND OF ECTOMYCORRHIZAS IN THE RESPONSE OF DOUGLAS-FIR SEEDLINGS TO DRYING SOIL
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DOI：
10.1111/j.1469-8137.1991.tb04914.x
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发表时间：
1991-02-01
期刊：
影响因子：
9.4
通讯作者：
LINDERMAN, RG
中科院分区：
文献类型：
--
作者：
DOSSKEY, MG;BOERSMA, L;LINDERMAN, RG
道格拉斯冷杉[Pseudotsuga menziesii（Mirb.）Franco]幼苗接种不同种类的外生菌根真菌Rhizopogon vinicolor FSL 788 -5、漆蜡伞S238-A或Hebeloma crustuliniforme HeCr 2，以确定不同真菌如何影响幼苗对干燥土壤的光合作用和水分关系的响应。 盆栽幼苗在温室中充分浇水培养6个月后，转移到生长室中，在土壤干燥时进行测量。与非菌根对照相比，Raphogon提高了净光合速率和气孔导度在-0.05 ~-0.50MPa的土壤水势范围内，尽管叶水势降低0.2 ~ 0.3MPa，但对土壤水分胁迫的影响仍极显著（P < 0.01）。 在此范围内，Hebeloma有提高叶片光合速率和气孔导度的趋势，而Laccaria则降低叶片光合速率和气孔导度，但两种真菌均不影响叶片水势。 我们的观察Rampogon和Laccaria不能解释现有的假设的基础上菌根对植物的大小，营养，渗透调节，或吸水特性的影响。 营养可能是一个因素Hebeloma.We建议，在没有营养和水分吸收的影响，净光合速率和气孔导度与光合产物的出口率的菌根真菌。 菌根对光合产物的强烈需求刺激光合作用，尽管有水分胁迫，气孔仍通过开放来响应。 我们的研究结果与这一假设是一致的。
Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings were inoculated with different species of ectomycorrhizal fungi, Rhizopogon vinicolor FSL788-5, Laccaria laccata S238-A, or Hebeloma crustuliniforme HeCr2, to determine how different fungi affect the response of photosynthesis and water relations of seedlings to drying soil. Potted seedlings were grown in a greenhouse for 6 months under well-watered conditions, then transferred to a growth chamber where measurements were made as the soil dried.Rhizopogon enhanced both net photosynthesis rate and stomatal conductance compared to non-mycorrhizal controls (P < 0.01) over the soil water potential range of -0.05 to -0.50 MPa, despite 0.2 to 0.3 MPa lower leaf water potential. Hebeloma tended to enhance, while Laccaria decreased net photosynthesis rate and stomatal conductance of host seedlings over this range of soil water potential, but neither fungus affected leaf potential. Our observations for Rhizopogon and Laccaria could not be explained by existing hypotheses based on mycorrhizal effects on plant size, nutrition, osmotic adjustment, or water uptake characteristics. Nutrition may have been a factor for Hebeloma.We propose that in the absence of nutritional and water uptake effects, net photosynthesis rate and stomatal conductance are correlated with rate of export of photosynthate to the mycorrhizal fungus. Strong mycorrhizal demand for photosynthate stimulates photosynthesis, to which stomata respond by opening, notwithstanding water stress. Our results for Rhizopogon are consistent with this hypothesis.