Physiological and biochemical changes in plants exposed to high temperatures may lower their resistance to diseases. In this regard, this study investigated whether thermal oscillations could change wheat resistance to blast, caused by Pyricularia oryzae, considered one of the most important diseases affecting wheat production. Plants were kept in two growth chambers with temperatures of 19 and 28 °C each for five days for thermal acclimatization and inoculated with P. oryzae after that. After inoculation, groups of plants were transferred to their original growth chambers (19 and 28 °C) and switched to growth chambers with temperatures different from those used for acclimatization (from 19 °C to 28 °C and from 28 °C to 19 °C) during three days. Plants subjected to thermal condition (TC) of 19 °C→19 °C compared to TC of 28 °C→28 °C showed lower blast symptoms. Photosynthetic impairment (lower maximum photosystem PSII photochemical efficiency, effective PSII quantum yield, quantum yield of non-regulated energy dissipation and stomatal conductance values and high internal CO₂ concentration) and lower concentrations of total chlorophyll a+b and carotenoids were noticed for plants subjected to 28 °C before or after inoculation. Inoculated plants subjected to TC of 28 °C→28 °C showed higher superoxide dismutase and lower ascorbate peroxidase activities. Lower superoxide anion and high hydrogen peroxide concentrations occurred for inoculated plants subjected to TC of 28 °C→28 °C. Higher chitinase, phenylalanine ammonia-lyase, and peroxidase activities occurred for inoculated plants subjected to TC of 28 °C→28 °C and 19 °C→28 °C and lower polyphenoloxidase activity for inoculated plants subjected to 28 °C after or before inoculation. Plants continuously subjected to 28 °C, before or after inoculation, displayed remarkable damage to their photosynthetic apparatus, a less robust antioxidative system, and a minor contribution of defense-related enzymes to counteract the deleterious effect of P. oryzae infection.

暴露于高温下的植物的生理和生化变化可能会降低其对疾病的抵抗力。在这方面，本研究调查了热振荡是否会改变由稻瘟病菌引起的小麦对稻瘟病的抗性，稻瘟病被认为是影响小麦生产的最重要疾病之一。将植物分别置于两个温度分别为19和28°C的生长室中进行热适应5天，并用米糠假单胞菌接种。之后。接种后，将几组植物转移到其原始生长室（19和28°C），并切换到温度与适应环境不同的生长室（从19°C到28°C和从28°C到19°C） C）在三天内。与28°C→28°C的TC相比，处于19°C→19°C的热条件（TC）的植物显示出较低的爆炸症状。光合损伤（较低的最大光系统PSII光化学效率，有效的PSII量子产率，不受控的能量耗散和气孔电导值以及较高的内部CO ₂浓度的量子产率）和较低的总叶绿素a + b浓度在接种之前或之后，在28°C的植物中都发现了类胡萝卜素和类胡萝卜素。温度为28°C→28°C的接种植物显示出较高的超氧化物歧化酶和较低的抗坏血酸过氧化物酶活性。在TC为28°C→28°C的条件下，接种过的植物中较低的超氧阴离子和较高的过氧化氢浓度。接种后或之前，温度在28°C→28°C和19°C→28°C的接种植物中，几丁质酶，苯丙氨酸氨裂合酶和过氧化物酶活性较高，而在28°C下接种的植物中，多酚氧化酶活性较低。 。在接种之前或之后，连续承受28°C的植物对其光合设备（一种较弱的抗氧化系统）显示出显着的损害，米曲霉感染。