Lorio Peter L., Sommers Robert A.
USDA, Forest Service, Southern Forest Experimental Station, 2500 Shreveport Highway, Pineville, LA 71360, USA.
Tree Physiol. 1986 Dec;2(1_2_3):301-306. doi: 10.1093/treephys/2.1-2-3.301.
A group of 10 pines (Pinus taeda L.) in a 35-year-old stand in Central Louisiana was sampled periodically from March through December 1984 for oleoresin flow from small wounds. Oleoresin yield was closely associated with periods of calculated moderate soil water deficit and presumed growth reduction. The period of maximum oleoresin flow coincided with the period of calculated maximum soil water depletion. Calculated potential evapotranspiration reached a maximum in late June, but water deficits did not reach maximum levels until September. Apparently, moderate seasonal water deficits that limit growth, but do not limit photosynthesis and translocation of photosynthates, favor differentiation processes, such as oleoresin synthesis. Because oleoresin is a primary defense against southern pine beetle (Dendroctonus frontalis Zimm.) attack in pines, recognition of these relationships should contribute to an understanding of southern pine beetle-host tree interactions.
1984年3月至12月期间，对路易斯安那州中部一片35年树龄林分中的10株火炬松（Pinus taeda L.）进行定期采样，以测定小伤口处的树脂流量。树脂产量与计算得出的中度土壤水分亏缺期以及假定的生长减缓期密切相关。树脂流量最大的时期与计算得出的土壤水分消耗最大的时期一致。计算得出的潜在蒸散量在6月下旬达到最大值，但水分亏缺直到9月才达到最高水平。显然，适度的季节性水分亏缺会限制生长，但不会限制光合作用和光合产物的转运，有利于诸如树脂合成等分化过程。由于树脂是松树抵御南方松甲虫（Dendroctonus frontalis Zimm.）侵害的主要防御物质，认识到这些关系应有助于理解南方松甲虫与寄主树之间的相互作用。
