Climate change can be described as a long-term, significant difference in average weather [22]. Like other agricultural crops, cucumber production also depends on environmental/climatic conditions for a better yield. In general, farmers face losses in the form of low productivity due to climate change [22,23,24]. This temperature variation can affect vegetable crops. As the optimum temperature for cucumber growth is between 20 and 25 °C, temperatures of around 35 °C can induce heat stress in the plants [25]. Stress has been well studied for reducing crop production and accelerating fruit ripening, which affects fruit quality [26]. Elevated temperature suppresses photosynthetic processes by modulating enzymatic activity, mainly Rubisco and other related enzymes [10] and the electron transport chain [27], resulting in the impairment of chlorophyll biosynthesis [11]. High temperature can also indirectly affect the photosynthetic process by increasing leaf surface temperature and affecting stomatal conductance [28,29]. Elevated temperatures not only affect the above ground parts of plants, but also significantly affect the root system. Heat in the root zone significantly reduces plant height, stem diameter, shoot fresh weight, shoot dry mass, and shoot water content of cucumbers.

The duration of initiation and expansion of floral organs and leaves is shortened by warming, leaving less time for biomass accumulation, ultimately resulting in reduced plant size [30,31]. Higher temperatures (42 °C) also suppress seed germination in cucumbers, thereby reducing plant growth and reproductive traits. In cucumbers, increasing temperature has a detrimental effect on sex expression, flowering, pollination and fruit set. High temperatures and long days tend to keep the vines in the male phase, while short days and low temperatures encourage more female flowers. Thus, an increase in temperature may reduce the number of female flowers, which indicates lower productivity [32,33]; male flowers are increased, but they are smaller and have reduced nectar, which will affect pollination, and pollen per flower also decline. In addition, early flowers in cucumber may drop when exposed to extremely high temperatures [34,35]. At the stage of fruit development, if the cucumber plant is exposed to high temperature, it will cause bitterness in the fruit [34]. High temperatures exert significant effects on various physiological characteristics in cucumbers, including changes in malondialdehyde (MDA) content and the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) enzymes [11,36]. These studies provide scientific evidence for the effects of high temperature on cucumber physiology [37,38]. In addition, high temperatures have been found to disrupt normal flower development in cucumbers by inducing pollen sterility [36]. Leaf wilting, physical damage to plant shoot and root growth, physiological disorders, biochemical changes and reproductive problems also result in a significant reduction in crop yield at high temperatures [39,40].

Drought is another major limiting factor for agricultural crops and, when combined with high temperatures, can affect the vitality of crops [41]. Depending on the species, yield losses under drought stress can range from 30 to 90 percent for sensitive crops. [42]. If plants can adapt their physiology to a drought environment, they will have a better chance of surviving. Higher temperatures may increase the ability of the environment to absorb more water vapor, resulting in more evapotranspiration by plants, which will lead to higher water requirements. Increase plant water demand could deplete the reservoir of water in the cultivating soil, creating a state of plant water stress (EPA, 2021). In dry and semidry climates, drought stress is the major factor that negatively affects plant growth and production, and undoubtedly reduces crop productivity [43,44,45,46,47]. Drought stress can reduce agricultural production by decreasing the activity of enzymes involved in the Calvin cycle [48,49,50].

The presence of drought results in numerous physiological, biochemical, morphological and molecular changes [43,44], including vascular tissue contraction, decreased water uptake [51] and impaired photo assimilate translocation [52]. In addition, drought inhibits ion uptake, impairs ATP biosynthesis and ROS accumulation, which accelerates oxidative damage and ultimately reduces plant development [53]. According to González Villagra et al. [54], drought stress disrupts the production of endogenous phytohormones by increasing ABA concentrations, decreasing IAA and GAs, and rapidly decreasing zeatin concentrations. The hormonal imbalance slows down the growth of plant cells by reducing their turgor, elongation and volume, leading to a decrease in growth characteristics [51]. Liu et al. (2018) conducted a study that demonstrated the negative effects of drought on cucumber seedlings, specifically showing a decrease in leaf thickness [55]. This can be attributed to a simultaneous decrease in the thickness of both the palisade and spongy layers. The study provides evidence of drought effects on cucumber seedling morphology. In addition, an Indian research group conducted a descriptive study on different cucumber genotypes and showed that drought also leads to a reduction in fruit yield per vine [56]. The study highlighted that different cucumber genotypes have different responses to drought stress. Farag et al. (2019) conducted a study that focused on the effect of drought stress on cucumber yield and its components [56]. The results of the study showed a significant decrease in yield, including a reduction in the number of fruits per plant, fruit weight per plant, and total yield, when compared to well-watered plants.

In addition, severe drought stress was found to have extensive detrimental effects on various aspects of cucumber growth and development. Metwaly et al. (2022) reported that severe drought significantly reduced vine length, fresh leaf weight, number of branches per plant, leaf number per plant, photosynthetic pigment content, and leaf area per plant [57]. These results provide evidence for the widespread negative effects of severe drought on cucumber plants. The very first response of plants to drought is stomatal closure. Further, as drought stress continues, plants induce other acclimation responses, such as cell wall modification and antioxidant production [58,59].