Physiology and growth of maize under salinity of water and application of hydrogen peroxide

ABSTRACT The salinity of irrigation water or soil is the abiotic factor that most negatively impacts the yield of crops, including green maize, so it is necessary to find alternatives to ensure production. In this context, this study aimed to evaluate gas exchange, photosynthetic pigments, and growth of maize under salinity of irrigation water and application of hydrogen peroxide. The experiment was conducted at the Center of Sciences and Agrifood Technology, Pombal, PB, belonging to the Federal University of Campina Grande, in the period from January to February 2015, using the maize hybrid ‘AG 1051’. The treatments consisted of two salinity levels of irrigation water (0.3 and 2.0 dS m-1) and five concentrations of hydrogen peroxide (0, 40, 80, 160, and 320 µmol L-1) applied via irrigation water. The experimental design was completely randomized, in a 2 × 5 factorial scheme, with four replicates. ECw of 2.0 dS m-1 reduces transpiration, stomatal conductance, total chlorophyll, carotenoids, and initial growth, but does not affect the dry mass accumulation of maize plants. Application of H2O2 via soil varying from 0 to 320 µmol L-1 causes reductions in the CO2 assimilation rate and transpiration, as well as at concentrations from 0 to 160 µmol L-1 for stomatal conductance of plants irrigated with ECw of 2.0 dS m-1. Application of H2O2 via soil up to a concentration of 320 µmol L-1 increases the plant height, but reduces culm diameter of maize.

摘要 灌溉水或土壤盐分是对包括鲜食玉米在内的作物产量影响最为负面的非生物胁迫因子（abiotic factor），因此亟需探寻保障农业生产的可行途径。在此背景下，本研究旨在探究灌溉水盐分胁迫与过氧化氢（hydrogen peroxide）施用对玉米气体交换参数、光合色素及生长状况的影响。本试验于2015年1—2月在坎皮纳格兰德联邦大学（Federal University of Campina Grande）位于巴西帕拉伊巴州蓬巴尔市的农业食品科技科学中心开展，供试玉米品种为杂交种‘AG 1051’。试验设置2个灌溉水电导率（ECw）水平（0.3与2.0 dS·m⁻¹）以及5个过氧化氢施用浓度（0、40、80、160、320 μmol·L⁻¹），所有处理均通过灌溉水施加。试验采用完全随机设计，为2×5因子布局，设置4次重复。结果表明，灌溉水电导率为2.0 dS·m⁻¹时，玉米的蒸腾速率、气孔导度、总叶绿素含量、类胡萝卜素含量及初期生长均受到显著抑制，但对植株干物质积累无显著影响。当灌溉水盐分浓度为2.0 dS·m⁻¹时，土施0~320 μmol·L⁻¹的过氧化氢会降低玉米的CO₂同化速率与蒸腾速率；当过氧化氢浓度处于0~160 μmol·L⁻¹区间时，灌溉该盐分浓度水的玉米植株气孔导度同样会出现下降。土施最高浓度达320 μmol·L⁻¹的过氧化氢可提升玉米株高，但会降低其茎秆直径。