Heat stress can have devastating effects on agricultural production and crop productivity. This study was conducted to evaluate the effect of exogenously applied thiourea on heat stress tolerance through osmotic adjustment in camelina (Camelina sativa L.). The study comprised of three factors: i) Heat stress; HS₀ = 25 °C (control) and HS₁ = 35 °C (stress), ii) camelina genotypes; G₁ = 611 and G₂ = 618, and iii) thiourea; TU₀=control-no thiourea supplementation, TU₁=thiourea supplementation (1000 mg/L) at vegetative stage (BBCH (Biologische Bundesanstalt Bundessortenamt and Chemical Industry) two codes scale-31), and TU₂=reproductive stage (BBCH two codes scale-59). Heat stress caused a reduction in the growth, carbon assimilation, and chlorophyll contents with more so where no thiourea was applied. Heat stress also caused a significant increase in lipid peroxidation (measured by leaf malondialdehyde contents), hydrogen peroxide, and electrolyte leakage in plants not receiving thiourea application. In addition, dry matter per plant, photosynthetic rate, and seed yield was reduced by 32.7, 40.8, and 60.9 %, respectively under elevated temperature as compared with control-no stress. However, the foliage applied thiourea alleviated the adverse effects of heat stress in camelina applied either at vegetative or reproductive growth stage by protecting the photosynthetic pigments (chlorophyll a, b) which helped to maintain photosynthetic efficiency by (14 %) than no thiourea applications). Foliar-applied thiourea also reduced oxidative damage by upregulating the antioxidants such as catalase, protease, and ascorbate peroxidase, and by improving osmolytes i.e., total soluble sugars, total soluble proteins, proline, and glycine betaine. Seed yield was improved by 57.8 % due to thiourea supplementation under heat stress compared with no thiourea application. Among the stages, thiourea application at the reproductive stage was more effective than the vegetative. Genotype 618 has produced highest dry weight per plant, photosynthetic efficiency, antioxidant activity under heat stress relative to genotype 611. In conclusion, thiourea application (1000 mg/L) improved heat tolerance in camelina by modulating gas exchange, antioxidant defense, and osmoprotectant. Thiourea application at the reproductive stage was more effective than the vegetative stage and 618 was heat stress tolerant genotype compared with genotype 611 which was relatively sensitive to heat stress.

热应激会对农业生产和作物生产力产生破坏性影响。本研究旨在通过渗透调节评估外源性应用硫脲对山茶（Camelina sativa L.）热应激耐受性的影响。该研究包括三个因素：i) 热应力；HS ₀  = 25 °C（对照）和 HS ₁  = 35 °C（应激），ii) 亚麻荠基因型；G ₁  = 611 和 G ₂  = 618，和 iii) 硫脲；TU ₀ = 对照 - 不添加硫脲，TU ₁ = 营养阶段添加硫脲 (1000 mg/L)（BBCH（Biologische Bundesanstalt Bundessortenamt and Chemical Industry）两个代码规模 - 31）和 TU ₂=生殖阶段（BBCH 两码标度-59）。热应激导致生长、碳同化和叶绿素含量降低，在不使用硫脲的情况下更是如此。热应激还导致未施用硫脲的植物中脂质过氧化（通过叶丙二醛含量测量）、过氧化氢和电解质泄漏显着增加。此外，与对照-无胁迫相比，在升高的温度下，单株干物质、光合速率和种子产量分别降低了 32.7%、40.8% 和 60.9%。然而，叶面喷施硫脲通过保护光合色素（叶绿素a , b)，这有助于将光合效率保持 (14 %)，而不是不使用硫脲）。叶面喷施硫脲还通过上调抗氧化剂（如过氧化氢酶、蛋白酶和抗坏血酸过氧化物酶）以及改善渗透物（即总可溶性糖、总可溶性蛋白质、脯氨酸和甘氨酸甜菜碱）来减少氧化损伤。与不施用硫脲相比，由于在热胁迫下补充硫脲，种子产量提高了 57.8%。各阶段中，繁殖期施用硫脲的效果优于营养期。与基因型 611 相比，基因型 618 在热胁迫下产生最高的单株干重、光合效率和抗氧化活性。 总之，硫脲应用 (1000 mg/L) 通过调节气体交换、抗氧化防御、和渗透保护剂。生育期施用硫脲比营养期更有效，618是耐热基因型，而611基因型对热胁迫相对敏感。