Abstract

Salinity commonly affects photosynthesis and crop production worldwide. However, some studies have shown that hydrogen peroxide seed priming can increase the tolerance of plants to salt stress. In this context, this study aimed to test the hypothesis that the H₂O₂ seed priming can improve photosynthetic efficiency in sunflower plants under salt stress. The experiment was conducted in a completely randomized design, with four replicates. Six treatments were tested: control (deionized water); salt control (100 mM NaCl); 0.1 mM H₂O₂ (36 h) + 100 mM NaCl; 1 mM H₂O₂ (24 h) + 100 mM NaCl; 10 mM H₂O₂ (12 h) + 100 mM NaCl; and 100 mM H₂O₂ (12 h) + 100 mM NaCl. Compared to the control treatment, leaf, stem and root dry mass of stressed plants showed 73, 76, and 71% reduction, respectively. However, this effect was less pronounced in plants whose seeds were primed with H₂O₂. After five weeks, H₂O₂ seed priming increased the CO₂ assimilation rate by 26%, instantaneous carboxylation efficiency by 38%, potential quantum yield and quantum yield of photochemical quenching of photosystems II by 22%, electron rate transport by 43%, and the chlorophyll b content by 71%. In addition, it reduced the non-photochemical quenching parameters by 22% compared to plants under salt control treatment.

摘要

盐度通常会影响全球的光合作用和作物生产。然而，一些研究表明，过氧化氢种子引发可以增加植物对盐胁迫的耐受性。在此背景下，本研究旨在检验H ₂ O ₂种子引发可以提高盐胁迫下向日葵植物光合效率的假设。该实验以完全随机设计进行，重复四次。测试了六种处理：对照（​​去离子水）；盐控制（100 mM NaCl）；0.1 mM H ₂ O ₂ (36 h) + 100 mM NaCl；1 mM H ₂ O ₂ (24 h) + 100 mM NaCl；10 mM H ₂ O ₂ (12 h) + 100 mM NaCl；和 100 毫米 H₂ O ₂ (12 h) + 100 mM NaCl。与对照处理相比，受胁迫植物的叶、茎和根干质量分别降低了 73%、76% 和 71%。然而，这种效果在种子用 H ₂ O ₂引发的植物中不太明显。五周后，H ₂ O ₂种子引发使CO ₂同化率提高了26%，瞬时羧化效率提高了38%，光系统II的潜在量子产率和光化学猝灭的量子产率提高了22%，电子速率传输提高了43%，和叶绿素b含量达 71%。此外，与盐控处理的植物相比，它的非光化学猝灭参数降低了 22%。