Abstract

The increase in the availability of phosphorus (P) can reduce the toxicity of copper (Cu) to plants because it favors the formation of complexes and precipitates, reducing the bioavailability of this metal. The objective of this study was to investigate the capacity of P supplementation to decrease the phytotoxicity of excess Cu in the growth and in physiological parameters of wheat plants. Plants of wheat (Triticum aestivum L.) were cultivated on sand substrate and, for 30 days, submitted to the control treatments - Hoagland & Arnon solution 100% (H&A); H&A + 47 mg P L⁻¹ (H&A + P); H&A + 28 Cu mg L⁻¹ (H&A + Cu); H&A + 47 mg P L⁻¹ + 28 mg Cu L⁻¹ (H&A + P + Cu). Plant growth, tissue nutrient concentration, photosynthetic pigment concentration, chlorophyll a fluorescence and superoxide dismutase enzyme activity in the leaves were evaluated. We observed that the treatments H&A + P and H&A + Cu provided higher height, while H&A + P + Cu provided higher dry matter yield of shoots and roots in plants. A higher Cu content in the leaves was observed in the plants cultivated with addition of 28 mg Cu L⁻¹, however the application of Cu did not cause loss of photochemical energy and energy dissipation in the PSII antenna complex. The addition of 47 mg P L⁻¹ provided a higher rate of electron transport in wheat plants. Therefore, wheat plants were tolerant to increasing the concentration of Cu in the culture medium and the addition of P attenuated the toxic effects caused by Cu, mainly in the roots of plants.

摘要

磷 (P) 可用性的增加可以降低铜 (Cu) 对植物的毒性，因为它有利于络合物和沉淀物的形成，从而降低了这种金属的生物利用度。本研究的目的是研究磷补充剂降低过量铜对小麦植物生长和生理参数的植物毒性的能力。将小麦 ( Triticum aestivum L.) 植株种植在沙质基质上，并进行 30 天的对照处理 - Hoagland & Arnon 溶液 100% (H&A)；H&A + 47 mg PL ^-1 (H&A + P)；H&A + 28 Cu mg L ^-1 (H&A + Cu)；H&A + 47 mg PL ^-1 + 28 mg Cu L ^-1(H&A + P + Cu)。评估了植物生长、组织营养浓度、光合色素浓度、叶绿素a荧光和叶子中的超氧化物歧化酶活性。我们观察到 H&A + P 和 H&A + Cu 处理提供了更高的高度，而 H&A + P + Cu 提供了更高的植物芽和根干物质产量。在添加28 mg Cu L ^-1栽培的植物中观察到更高的Cu含量，但是Cu的应用不会导致PSII天线复合物中的光化学能和能量耗散的损失。添加 47 mg PL ^-1为小麦植物提供了更高的电子传输速率。因此，小麦植物耐受培养基中Cu浓度的增加，并且P的添加减弱了Cu引起的毒性作用，主要是在植物的根部。