Drought is a harmful abiotic factor that clearly affects the growth and production of plants. The negative impacts of drought can be reduced by ascorbic acid (AsA) which is an important non-enzymatic antioxidant in plants. The purpose of the current investigation was to study the effects of different levels of drought and the external application of AsA on sweet pepper plants. The experiment had two factors, the first factor was drought: irrigation within the field capacity, moderate stress (irrigation within the 60% field capacity) and severe stress (irrigation within the 30% field capacity). The second factor was AsA: 0 mM sprayed with distilled water, 0.5 and 1 mM. The experiment had three replications. The results illustrated that drought stress reduced the fresh and dry weight of roots and shoots. It also reduced the relative water content (RWC), diameter and length of fruit, chlorophyll content and leaf area. Drought stress increased the activity of polyphenol oxidase and ascorbate peroxidase enzymes. It caused improvements in antioxidant properties, total phenolic content, ascorbate and electrical conductivity (EC) in the leaves of sweet pepper. Higher concentrations of AsA by foliar application significantly increased the values of all measured parameters except the EC. The interaction between ascorbic acid and drought stress showed that ascorbic acid significantly increased the shoot fresh weight, root dry weight, antioxidant properties, ascorbate, polyphenol oxidase and ascorbate peroxidase. However, it reduced the electrical conductivity. It is claimed that sweet pepper plants acquire tolerance to drought because AsA contributes to an increase in antioxidant properties.

干旱是有害的非生物因素，显然会影响植物的生长和生产。抗坏血酸（AsA）是植物中一种重要的非酶抗氧化剂，可减少干旱的负面影响。当前研究的目的是研究不同水平的干旱和AsA在甜椒植株上的外部施用。该实验有两个因素，第一个因素是干旱：田间容量内的灌溉，中等压力（60％田间容量内的灌溉）和严重胁迫（30％田间容量内的灌溉）。第二个因素是AsA：用蒸馏水喷洒0 mM，0.5和1 mM。实验重复了三遍。结果表明，干旱胁迫降低了根和茎的鲜重和干重。它还降低了相对含水量（RWC），果实直径和长度，叶绿素含量和叶面积。干旱胁迫增加了多酚氧化酶和抗坏血酸过氧化物酶的活性。它改善了甜椒叶中的抗氧化剂，总酚含量，抗坏血酸和电导率（EC）。叶面喷施较高浓度的AsA会显着增加除EC以外的所有测量参数值。抗坏血酸与干旱胁迫之间的相互作用表明，抗坏血酸显着增加了枝条的鲜重，根干重，抗氧化剂，抗坏血酸，多酚氧化酶和抗坏血酸过氧化物酶。但是，它降低了电导率。