Laboratório da Interação Planta-Patógeno, Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais State 36570-900, Brazil.
Phytopathology. 2019 Jul;109(7):1129-1140. doi: 10.1094/PHYTO-11-18-0428-R. Epub 2019 May 21.
Blast, caused by , has become a devastating disease on wheat in several countries worldwide. Growers need alternative methods for blast management, and silicon (Si) stands out for its potential to decrease the intensity of important diseases in several crops. This study investigated the effect of Si on improving photoassimilate production on flag leaves of wheat plants and their partitioning to spikes in a scenario where blast symptoms decreased as a result of potentiation of defense mechanisms by Si. Wheat plants (cultivar BRS Guamirim) were grown in hydroponic culture with 0 or 2 mM Si and inoculated with at 10 days after anthesis. The Si concentration on flag leaves and spikes of Si-supplied plants increased and resulted in lower blast symptoms. High concentrations of total soluble phenols and lignin-thioglycolic acid derivatives and greater peroxidase, polyphenoloxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, and chitinase activity occurred on flag leaves and spikes of Si-supplied plants and increased their resistance to blast. The concentration of photosynthetic pigments decreased and the photosynthetic performance of infected flag leaves and spikes from plants not supplied with Si was impaired for chlorophyll fluorescence parameters including maximal photosystem II quantum efficiency, fraction of energy absorbed used in photochemistry, quantum yield of nonregulated energy dissipation, and quantum yield of regulated energy dissipation. The concentration of soluble sugars was lower on infected flag leaves and spikes from plants not supplied with Si, whereas the hexose-to-sucrose ratio increased on infected flag leaves. Sucrose-phosphate synthase activity was lower and acid invertase activity was higher on flag leaves and spikes of plants not supplied with Si, respectively, compared with Si-supplied plants. The starch concentration on spikes of Si-supplied plants increased. In conclusion, Si showed a beneficial effect in improving the source-sink relationship of infected flag leaves and spikes by preserving alterations in assimilate production and partitioning during the grain filling process.
由引起的爆炸已成为世界上几个国家小麦的毁灭性疾病。种植者需要替代的方法来管理爆炸，而硅（Si）因其能够降低几种作物重要疾病的强度而脱颖而出。本研究调查了 Si 对提高小麦植株旗叶光合作用产物及其向穗部分配的影响，在这种情况下，由于 Si 增强了防御机制，爆炸症状会减轻。小麦植株（品种 BRS Guamirim）在水培条件下用 0 或 2 mM Si 培养，并在开花后 10 天用接种。供 Si 植物的旗叶和穗中的 Si 浓度增加，导致爆炸症状减轻。高浓度的总可溶性酚类和木质素-硫代乙二醇酸衍生物以及更高的过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶、β-1,3-葡聚糖酶和几丁质酶活性发生在供 Si 植物的旗叶和穗上，增加了它们对爆炸的抗性。供 Si 植物的感染旗叶和穗中的光合色素浓度降低，未供 Si 植物的感染旗叶和穗的叶绿素荧光参数包括最大光系统 II 量子效率、用于光化学的吸收能量的分数、非调节能量耗散的量子产率和调节能量耗散的量子产率的光合性能受损。未供 Si 植物的感染旗叶和穗中的可溶性糖浓度较低，而感染旗叶中的己糖-蔗糖比增加。与供 Si 植物相比，未供 Si 植物的旗叶和穗中的蔗糖磷酸合酶活性较低，酸性转化酶活性较高。供 Si 植物的穗中的淀粉浓度增加。总之，Si 通过在灌浆过程中保持同化产物的产生和分配的改变，对改善感染的旗叶和穗的源-库关系表现出有益的效果。
