Bioscience Evidence 2024, Vol.14, No.6, 281-292 http://bioscipublisher.com/index.php/be 286 xanthophyll cycle, which dissipates excess light energy as heat, thus preventing damage to the photosynthetic apparatus (Espley and Jaakola, 2023). Additionally, the orientation of the cladodes (modified stems) can be adjusted to minimize direct sunlight exposure, further enhancing light management. Table 1 Evaluation of appearance and soluble solids content after tree treatment (Adopted from Xu et al., 2024) Group Indicators Days after flowering 20d 25d 30d 35d 40d 45d Treatment Group Weight (g) 370 424 487 510 515 517 Sweetness (% Brix) 11 15 17 21 20.5 20 Scale integrity Intact Intact Intact Intact Intact Intact Fruit surface color Green Yellow Yellow Yellow-green Green Green Control group Weight (g) 359 410 458 472 480 473 Sweetness (% Brix) 11 15 17 18 17 15 Scale integrity Intact Intact Dry tips Withered Withered Cracked Fruit surface color Green Yellow Yellow Yellow-green Yellow-green Yellow-green 5.2 Temperature tolerance and adaptation Temperature is another critical factor influencing the growth and development of Hylocereus spp. These plants are highly adapted to withstand high temperatures, typical of arid and semi-arid environments, where they often thrive. Optimal growth occurs between 18 ℃ and 35 ℃, but they can tolerate temperatures as high as 40 ℃ (Chu and Chang, 2020). In response to heat stress, Hylocereus spp. employ several physiological mechanisms, including the upregulation of heat shock proteins (HSPs) and the stabilization of cell membranes (de Oliveira et al., 2021). These adaptations help maintain cellular homeostasis and prevent thermal damage to enzymes involved in metabolic processes. Conversely, Hylocereus spp. are sensitive to low temperatures, particularly frost, which can cause tissue damage and necrosis. To mitigate the effects of cold stress, these plants may accumulate osmolytes such as proline and soluble sugars, which act as cryoprotectants by stabilizing cellular structures and maintaining osmotic balance. 5.3 Response to water availability The ability of Hylocereus spp. to adapt to water scarcity is one of its most distinctive features, enabling it to thrive in environments with irregular rainfall. As CAM (Crassulacean Acid Metabolism) plants, dragon fruit species exhibit a unique water-conserving strategy by opening their stomata at night to minimize water loss during photosynthesis (Wang et al., 2019; Jalgaonkar et al., 2022). During periods of drought, Hylocereus spp. can shift their CAM activity towards a more conservative water-use mode, characterized by reduced stomatal opening and increased water-use efficiency (Wang et al., 2019). The fleshy stems serve as water reservoirs, storing large quantities of water that sustain the plant during prolonged dry spells. Additionally, the root system of Hylocereus spp. is adapted to maximize water uptake from the soil, with a high density of fine roots that can rapidly absorb moisture from transient rainfalls (Wakchaure et al., 2023). These adaptations collectively enhance the plant’s drought tolerance, making Hylocereus spp. a resilient crop for cultivation in arid and semi-arid regions. 6 Case Studies 6.1 Liquid culture system enhances dragon fruit micropropagation efficiency Dragon fruit (Hylocereus spp.) exhibits remarkable adaptability in arid and semi-arid environments, which is crucial for cultivation in water-deficient areas (Wakchaure et al., 2023). However, conventional propagation methods are limited by low multiplication rates and high production costs. Some studies have explored methods to improve large-scale micropropagation of dragon fruit using automated liquid culture systems (Dewir et al., 2023; Lee and Chang, 2024). For example, a study on the large-scale micropropagation of red-fleshed dragon fruit (Hylocereus polyrhizus) using an automated liquid culture system and arbuscular mycorrhizal fungi (AMF) demonstrated that the proliferation of axillary buds in a continuous immersion air-lift bioreactor system
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