Phytopathology. 1997 Apr;87(4):422-8. doi: 10.1094/PHYTO.1997.87.4.422.
ABSTRACT The aggressiveness of Sphaeropsis sapinea isolates was compared on water-stressed and nonstressed 3-year-old red pines (Pinus resinosa) in greenhouse and growth chamber experiments. Water was withheld from stressed seedlings to achieve mean predawn needle water potentials (psi(PD)) above -1.9 MPa. The lowest mean psi(PD) of well-watered seedlings was maintained at or above -0.8 MPa. Young shoots were inoculated by placing colonized agar plugs on wounds made by removing a needle fascicle. Two isolates of each recognized morphotype (A and B) were used in the greenhouse experiment and two isolates of morphotype A were used in the growth chamber experiment. After 4 weeks, isolates of morphotype A caused more severe symptoms and could be recovered farther from the inoculation site on water-stressed than on nonstressed trees in both experiments. In the greenhouse experiment, isolates of mor-photype A also caused more severe symptoms and could be recovered farther from the inoculation site than isolates of morphotype B, regardless of watering regime. These results indicate that water stress at levels observed typically in the field can result in increased disease development by isolates of S. sapinea morphotype A on red pine. The reduction of water stress of red pines in the field may reduce losses due to Sphaeropsis shoot blight.
摘要 在温室和生长室实验中，比较了球腔菌不同分离株在胁迫和非胁迫 3 年生湿地松（Pinus resinosa）上的侵袭性。通过不给胁迫苗浇水来实现平均晨始针叶水势（psi(PD))高于-1.9 MPa。充分浇水的幼苗的最低平均 psi(PD)保持在-0.8 MPa 或以上。通过去除针束来制造伤口，然后将已定植的琼脂塞放在伤口上接种嫩枝。在温室实验中使用每个公认形态型（A 和 B）的两个分离株，在生长室实验中使用形态型 A 的两个分离株。4 周后，形态型 A 的分离株在水胁迫下比在非胁迫下引起更严重的症状，并且可以从接种部位更远的地方恢复。在温室实验中，形态型 A 的分离株也引起了更严重的症状，并且可以比形态型 B 的分离株更远地从接种部位恢复，而与浇水制度无关。这些结果表明，在田间通常观察到的水平的水分胁迫会导致球腔菌形态型 A 的分离株在湿地松上的疾病发展加剧。减少野外湿地松的水分胁迫可能会减少由球腔菌嫩梢枯萎病引起的损失。
