Sunscreen Use Research Articles

Awareness and knowledge of sun exposure and use of sunscreen among adults in Aseer region, Saudi Arabia

BackgroundExcessive sun exposure and inadequate sunscreen use can lead to skin cancer and other harmful effects on the skin, eyes, and immune system. PurposeThis observational cross-sectional study aimed to assess awareness and knowledge of sun exposure and sunscreen use among adults in the Aseer region, Saudi Arabia. This study also focused on evaluating the risks of skin cancer and participants’ sun-protective attitudes and practices. MethodsA population-based cross-sectional study was conducted among adults in the Aseer region, Saudi Arabia. Data were collected using a questionnaire from November 2022 to January 2023 that assessed participants’ knowledge, practices, and beliefs regarding sun exposure and sunscreen use. A total of 400 participants were selected for the study. Approval for the study was granted by the Local Research Ethics Committee of the University of Bisha, Saudi Arabia. ResultsThe results revealed that (59.8 %) of the participants were female, while (40.3 %) were male. Regarding age, the majority fell within the 26–35 age range (37.5 %), with (16.0 %) of participants using sunscreen regularly, with a total of (74.0 %) of participants using sunscreen. Men exhibited a higher prevalence of negative attitudes towards sun protection, while women demonstrated more favourable sun protection practices. In addition, (1.25 %) of the participants had skin cancer in the past; (81.0 %) of participants agreed that skin cancer could cause death, while (19.0 %) were unsure of the effects of skin cancer. Moreover, the results indicated that sun exposure had a significant positive effect on awareness levels (p < 0.05), indicating that increased sun exposure was associated with higher awareness of the harmful effects of the sun. Additionally, awareness level significantly positively affected sunscreen use (p < 0.01), suggesting that individuals with higher awareness were more likely to use sunscreen. ConclusionThere was an average awareness of sun exposure and its detrimental effects. In addition, a significant portion of the population demonstrates proactive measures to minimize sunlight exposure. However, sunscreen usage among Saudi adults was low despite having knowledge and awareness. Future research must enhance sun protection practices and reduce sun-related skin damage in the Aseer region.

Formulation of phytosomes with sun protection factor using Agave americana ethanolic extract

Over-exposure to the sun’s ultraviolet rays is a major environmental risk factor for skin cancer. Shortcomings associated with the use of synthetic sunscreens can be overcome by the use of herbal based sunscreens. Plant phytochemicals have antioxidant activity and Sun Protection Factor (SPF) activity, however their hydrophilic nature limits their ability to penetrate into deeper areas of the skin thereby affecting their bioavailability. The aim of this study was to formulate phytosomes with antioxidant and SPF activity using ethanolic extracts of Agave americana americana and Agave americana marginata leaves. Soxhlet extraction was used to extract phytochemicals from dried leaves. The presence of phenols, flavonoids, and tannins were confirmed using various tests. The antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay while SPF activity was determined using UV spectroscopy. Phytosomes were formulated and characterized for size, Polydispersity Index (PDI) and zeta potential. A. americana americana had a higher content of flavonoids, phenols, and tannins which also resulted in better antioxidant activity (IC50) 4.77 μg/ml versus 5.66 μg/ml and SPF activity of 9.95 versus 5.84, when compared to A. americana marginata. The phytosome formulations using A. americana americana had SPF activity of 9.96 to 13.3 with 40 mg extract and 60 mg soy lecithin having the highest activity. This formulation had the smallest particle size of 91nm, PDI and zeta potential of 0.235 and -4.95, respectively. These results indicate the formulation of the extracts into phytosomes enhances their SPF activity.

A Review of the Optimal Effects of Sunscreen Usage in Women Residing in Tropical Climate Regions for Melasma Prevention: Insights from Literature Analysis

Melasma is a hyperpigmented patch that is generally found on the face, especially on the cheeks, chin, upper lip, and can extend to the neck. The color of hyperpigmentation in melasma varies, generally light brown to black with an irregular shape. Melasma is often found in countries with tropical climates with skin types III-V. This happens because countries with these climates are exposed to more sunlight. To reduce excessive UV exposure to the skin, you can use sunscreen. Optimal use of sunscreen must also be considered in order to reduce the incidence of melasma. This literature review uses four databases (Google scholar, PUBMED, NCBI and PERDOSKI) using the relevant keywords namely "melasma" and "sunscreen" to find the source of articles published in 2010 to 2022. The search results get 142 articles. in Indonesian and English. After selecting based on inclusion and exclusion criteria, 14 relevant articles were obtained which will be discussed in this literature review. In this literature review, the results show that there is a significant relationship between optimal use of sunscreen for women in countries with tropical climates, especially Asia, and the incidence of melasma. Melasma occurs mostly in women with Fitzpatrick III-V skin types and is susceptible to age 25-60 years. Patients with melasma who used sunscreen optimally by applying it every 2 hours showed a decrease in the degree of severity of melasma compared to those who did not repeat the use of sunscreen.

Evaluation of the photoprotective and antioxidant potential of an avobenzone derivative.

Solar radiation can cause damage to the skin, and the use of sunscreens is one of the main protective measures. However, photounstable ultraviolet (UV) filters can generate photoproducts and reactive oxygen species (ROS). Adding antioxidants, such as resveratrol, to enhance the action of UV filters in sunscreens is an interesting strategy for reducing the damage caused by UV radiation exposure. However, new compounds must have their stability, safety and efficacy guaranteed. Avobenzone, a commonly used UV filter, stands out as a promising candidate for structural modification to enhance its stability. Its molecular hybridization with other UV filters and antioxidants can lead to safer and more effective compounds. In this study, the photoprotective and antioxidant potential of a derivative of avobenzone, hybridized with resveratrol's molecule, was evaluated using in vitro models of cells in monolayer and reconstructed human skin (RHS). Phototoxic potential was assessed using fibroblasts, while the antioxidant activity was measured using the DCFH2-DA probe in HaCaT keratinocytes and in-house RHS. The derivative exhibited UV absorption and demonstrated photostability. It did not exhibit any phototoxic nor photoreactivity potential. Additionally, it was able to photo stabilize a combination of photounstable UV filters, avobenzone and octyl methoxycinnamate, and to reduce their phototoxic potential. In terms of antioxidant activity, the derivative successfully protected against UVA-induced ROS production in the HaCaT keratinocytes model, showing statistical equivalence to the antioxidant control, quercetin (10μg/mL). Furthermore, experiments conducted in the RHS model demonstrated a significant reduction of 30.7% in ROS generation compared to the irradiated control. This study demonstrated that structural modifications of avobenzone can lead to the development of a broad spectrum (absorbing UVB and UVA II radiation, as well as a portion of the UVA I radiation), non-phototoxic, non-photoreactive and photostable derivative for sunscreen and anti-aging formulations. This derivative enhances protection against oxidative stress induced by UV radiation and improves the effectiveness of sun protection. In addition to the monolayer model, the use of a standardized in-house RHS model was highly relevant for evaluating the effects of UV radiation and skin aging. This model closely mimics human physiological conditions and enables the testing of new compounds and the investigation of protective mechanisms against skin damage.

Evaluation of an advanced antioxidant and double-conjugated retinoid/AHA cream in participants with FST IV-V.

Topical antioxidants and retinoids are foundational components of an effective skincare regimen. Pyrroloquinoline quinone (PQQ) is a potent free radical scavenger that supports efficient mitochondrial energy creation. An advanced antioxidant combines topical allyl PQQ with existing WEL antioxidant technology (TAP) to comprehensively address extrinsic and intrinsic skin aging. In conjunction with TAP, a double-conjugated retinoid/alpha hydroxy acid (AHA-Ret) designed to minimize irritation and optimize delivery was used over 12 weeks to improve the appearance of photodamaged skin. Twice-daily application of TAP and nightly application of AHA-Ret was evaluated in female participants aged 40-65 years with FST IV-V and mild (3) to moderate (6) facial photodamage using a 10-point grading scale. Visible improvements from baseline in lines/wrinkles, skin texture, skin tone, skin dullness and erythema were assessed using a six-point grading scale (0 = None to 5 = Severe). Adverse Events (AEs) were captured throughout the study period. Participants (N = 21; mean age, 56 years) equally represented mild and moderate photodamage, and FST IV and V (41%, Hispanic; 36%, African American; and 32%, Caucasian). Significant mean improvements from baseline occurred in skin dullness, skin texture, and skin tone (all, p < 0.0001), and significant mean reductions from baseline were demonstrated in erythema and melanin at Week 12. Mild, transient AEs were reported. No participant discontinued study participation due to an AE. A skincare regimen comprised of an advanced antioxidant and AHA-Ret cream, in conjunction with daily use of a broad-spectrum sunscreen (SPF 56), led to significant improvements at 12 weeks in the appearance of photodamaged skin in females with FST IV and V.

SUN EXPOSURE IN CHILDHOOD: LASTING IMPACTS AND DAMAGE PREVENTION STRATEGIES

The study addresses childhood sun exposure, highlighting its importance and lasting impacts on children's health. It seeks to understand the specific implications of inadequate exposure, associating it with increased risk of skin cancer and other dermatological problems in adulthood. Preventive strategies, such as regular use of sunscreen and awareness of safe practices, are key to preventing damage. The implementation of an educational primer, prepared by the Brazilian Society of Dermatology, emerges as a crucial tool in the promotion of the health of children's skin. The resistance of children to the use of sunscreen can be addressed with innovative strategies, such as developing products specific for children. The lack of information among parents highlights the need for awareness programs in pediatric consultations, schools and communities. The study concludes that childhood sun exposure requires a proactive and educational approach, underlining the importance of continuous awareness to ensure a healthy future. Investment in education and public policy is crucial to address challenges related to childhood sun exposure.

Gambaran Tingkat Pengetahuan dan Perilaku Responden pada Penggunaan Sunscreen di Klinik Kecantikan Wilayah Bekasi

unlight contains ultraviolet rays that harm the skin, causing various kinds of skin disorders such as redness, premature aging, black spots, dryness, wrinkles, and skin cancer. Sunscreen is a skin care product that is useful for protecting the skin from the sun. This study aimed to determine the level of knowledge, attitudes, and behavior of female patients at the Beauty Clinic Region of Bekasi about the use of sunscreen. This study uses a descriptive method with a cross-sectional approach. The sample of 92 respondents at the Beauty Clinic Region of Bekasi was selected by purposive sampling by distributing questionnaires. The highest research results were obtained in the age group of 17-25 years as much as 38%, the Senior High School education group as much as 54,3%, the housewives occupation group as much as 35,9%, and private employees as much as 35,9%. The level of sufficient knowledge is 59,8%, sufficient attitude is 56,5% and sufficient behavior is 45,7%. Based on the results of this study, it can be concluded that the respondents at the Beauty Clinic Region of Bekasi have sufficient knowledge and behavior regarding the use of sunscreen.

When Arguments Meet a Story: An Experiment Testing Message Design Strategies for Skin Cancer Prevention and Detection

ABSTRACT Persuasion research often suggests combining different message formats such as facts, statistics, and narratives in message design to maximize persuasive effects. However, the effect of the combination, especially between fact-based arguments and long-form narratives, varies depending on many factors which have been understudied. Our study therefore tested how argument strength, argument position, and target behavior interacted in impacting behavioral outcomes for such a combined message about skin cancer. Findings from our experiment revealed a significant three-way interaction, as weak arguments were more effective when embedding them in a long-form narrative, whereas strong arguments were more impactful when placing them before the narrative. Such an interaction emerged only when messages recommended sunscreen use but not when recommending skin-self exams. We discussed the implications of the findings for message design about skin cancer prevention and detection.

EDUKASI PENGGUNAAN TABIR SURYA SEBAGAI UPAYA PENCEGAHAN KANKER KULIT PADA REMAJA DI PONDOK MODERN AL-KAUTSAR PEKANBARU

Skin cancer is one type of neoplasm that can be violent. One factor that can contribute to the occurrence of skin cancer is exposure to ultraviolet (UV) rays. Adolescents are an age group that has the potential to be exposed to UV rays longer and with high intensity. The use of sunscreen is recommended to prevent skin cancer due to UV exposure. The recommended use of sunscreens especially those containing SPF 30 or more. Providing education can increase knowledge and awareness in adolescents to prevent skin cancer and use sunscreen when outdoors. This community midwifery activity will be carried out in November 2023 at Pondok Modern Al-Kautsar Pekanbaru. The activity carried out was education to 30 teenagers about the use of sunscreen as an effort to prevent skin cancer. The activity was carried out first with a pre-test then continued with the presentation of material for 60 minutes and after that post test about skin cancer and the use of sunscreen. The results of activities in students and students there was an increase in skin cancer and the benefits of sunscreen in the prevention of skin cancer. It is expected for adolescents who will do outdoor activities to always use sunscreen according to recommendations to reduce the risk of skin cancer.

Vitamin D deficiency during the coronavirus disease 2019 (COVID-19) pandemic among healthcare workers

Vitamin D deficiency is a common nutritional problem worldwide that may have worsened during the coronavirus disease 2019 (COVID-19) pandemic. The present study sought to examine the prevalence and correlates of vitamin D deficiency among healthcare workers three years after the start of the COVID-19 pandemic. Participants comprised 2543 staff members from a medical research institute, who completed a questionnaire and donated blood samples in June 2023. 25-hydroxyvitamin D (25[OH]D) levels were measured using an electrochemiluminescence immunoassay. Logistic regression was used to calculate the odds ratio and its 95% confidence interval while adjusting for covariates. The proportions of participants with vitamin D insufficiency (25[OH]D 20-29ng/mL) and deficiency (25[OH]D<20ng/mL) were 44.9% and 45.9%, respectively. In a multivariable-adjusted model, factors associated with a higher prevalence of vitamin D deficiency included younger age, female sex, fewer hours of daytime outdoor physical activity during leisure time (without regular use of sunscreen), lower intake of fatty fish, no use of vitamin D supplements, smoking, and no alcohol consumption. Occupational factors, including shift work, were not independently associated with vitamin D deficiency. Our results suggest that vitamin D insufficiency and deficiency are highly prevalent among healthcare workers. Health education regarding lifestyle modifications for this occupational group are warranted to improve their vitamin D status in the COVID-19 era.

Prevalence of sunscreen use and sunburn in Greek athletes: a cross-sectional study.

Athletes participating in outdoor sports are in a high-risk category for prolonged sun exposure. This study investigates whether swimmers and beach volleyball athletes adopt appropriate measures to protect their skin from the sun. Sunscreens play a key role in protecting the skin from solar radiation and preventing premature aging. The study assesses the frequency of sunscreen use and the incidence of sunburn among athletes. Athletes completed a self-administered questionnaire regarding their sun protection and exposure habits. Participants aged 9 to 60 years, engaged in swimming (N.=1047) and beach volleyball (N.=785), were included in this study. In the group of swimmers (N.=858), a notable percentage never used sunscreen, and among those who did, (N.=137), natural products were predominantly applied. Gender differences revealed a significantly higher sunscreen usage (P<0.001) among female swimmers compared to males. Among beach volleyball athletes, sunscreen use was notably higher (90%), with 55.6% applying natural sunscreen and 44.4% opting for non-natural alternatives. Regarding the incidence of sunburn, the occurrence among both male and female swimmers was observed to be very low. Among those with sunburn, females exhibited a significantly higher frequency than males (P<0.001). Conversely, in beach volleyball athletes, sunburn affected a higher percentage of males (49.8%) than females (43.9%). Sunscreen utilization is notably insufficient among athletes, reflecting a limited awareness of the potential risks associated with sun exposure, even though they frequently suffer from sunburn. This heightened susceptibility places them at an increased risk of developing skin lesions. Initiating and disseminating awareness campaigns that specifically emphasize the importance of sunscreen use within the outdoor sports community is imperative.

Assessing the safety and efficacy of DIY-homemade sunscreens with natural, aromatic and herbal ingredients

Sunscreen products are widely used during the summer months to protect against increased sunlight exposure. While there have been advancements in the effectiveness and safety of commercial sunscreens, there is a growing interest in "completely natural" and homemade skincare products, including sunscreens. These homemade alternatives often incorporating aromatic and medicinal herbal preparations, are being touted as safe alternatives on online social media platforms and alternative health websites. It is essential to recognize that scientific research has primarily focused on evaluating the effectiveness and safety of commercially available sunscreen products. Concerns have arisen regarding the potential risks associated with non-commercial sunscreens, particularly those labeled as "homemade" or "completely natural." Therefore, it is crucial to investigate whether these DIY sunscreen products, advertised as natural and additive-free, pose any health threats due to their inadequate sun protection properties. This study aims to examine the formulations of these proposed homemade sunscreen products, specifically evaluating their durability, protection against ultraviolet A and B (UVA and UVB) radiation, and average sun protection factor (SPF) values from a toxicological perspective. Emphasizing the importance of safety in sunscreen products is paramount, as the use of unsafe sunscreens can lead to serious health risks, including skin cancer, premature aging, and other skin disorders.

Assessment of prevalence of sunscreen use and related practices among people living in Saudi Arabia: A cross-sectional survey-based study.

The use of sunscreen significantly reduces the risk of skin cancer and helps maintain skin health; however, improper use can decrease its effectiveness. This study aimed to investigate the prevalence and factors associated with sunscreen use in Saudi Arabia as well as identifying areas of weakness in sunscreen practices. A cross-sectional survey-based study was conducted with a diverse population sample in Saudi Arabia. Participants were asked about their sunscreen usage habits, motivations, and knowledge of proper application techniques. Demographic information, including age, gender, and skin type, were also collected. A total of 2321 individuals participated in the study. More than two-thirds of the participants reported using sunscreen either always, regularly, or often, primarily to maintain a light skin color and prevent skin cancer. Factors associated with sunscreen use included younger age (18-40 years old), female gender, history of sunburn, and fair skin. Despite the majority reporting healthy sun exposure habits, several shortcomings were identified in sunscreen practices, including incorrect application and suboptimal reapplication frequency. While sunscreen use is common among the study population, there is a need for improved education on proper application techniques. National awareness campaigns, especially those utilizing popular social media and digital platforms in Saudi Arabia, should focus on disseminating accurate sunscreen use guidelines to maximize sun protection and skin health.

Rural-Urban Differences in Sun Exposure and Protection Behaviors in the United States.

Evidence regarding whether rural residence is a risk factor for skin cancer is mixed. We compared sun exposure and protection behaviors between rural and urban residents by ethno-racial group in the United States. We analyzed data from three (2013-2018) National Health and Nutrition Examination Survey cycles. We compared self-reported sun exposure and protection measures (sunburn, time spent outside, sunscreen use, wearing long sleeves, staying in shade) by rural-urban residential status using survey-weighted logistic regression models stratified by ethno-racial group, adjusting for age, sex, income, education, body mass index, and smoking. Hispanic rural versus urban residents more often reported sunburns in the past year [41.6% vs. 31.2%, adjusted OR (aOR): 1.46 (1.15-1.86)]. White rural versus urban residents more often spent 2+ hours outside on workdays [42.9% vs. 29.1%, aOR: 1.60 (1.27-2.01)] and non-workdays [72.2% vs. 64.8%, aOR: 1.45 (1.12-1.88)] and less often used sunscreen [26.0% vs. 35.1%, aOR: 0.74 (0.59-0.93)] and stayed in the shade [21.7% vs. 26.7%, aOR: 0.72 (0.57-0.89)]. Black rural versus urban residents stayed in the shade less often [31.6% vs. 43.9%, aOR: 0.60 (0.39-0.91)] but less often spent 2+ hours outside on non-workdays [47.6% vs. 56.8%, aOR: 0.67 (0.51-0.90)]. Across all ethno-racial groups included, rural residents reported greater sun risk behaviors than urban residents, with some nuances by ethno-racial identity, suggesting rural residence is a potential risk factor for skin cancer. Sun protection promotion programs should consider rural-urban settings while also accounting for ethno-racial identities.

Hypovitaminosis D in university workers in Southern Ecuador: interactions between gender and lifestyle.

Hypovitaminosis D may be common in tropical countries and is linked to disorders of phospho-calcium metabolism, rickets, muscle pain, immune system deficiencies, and increased susceptibility to microbial infections. To assess the prevalence of hypovitaminosis D in apparently healthy university workers in Loja, Ecuador. A cross-sectional study was completed in a private Ecuadorian university from May 2023 to September 2023, involving 440 participants. Data were gathered using a structured questionnaire created to assess risk factors influencing vitamin D levels. Serum 25-hydroxyvitamin D (25-OH)D concentrations were measured utilizing immunoenzymatic methods. Altered states (insufficiency or deficiency) of vitamin D were defined with serum values <30 ng/mL. Associations between vitamin D status and selected determinants were analyzed with independence tests, with significance set at p < 0.05. Where possible, odds ratios (OR) were calculated using logistic regression. The sample consisted of 60.9% faculty members and 39.1% administrative staff; 42.7% were men and 57.3% were women, with an average age of 41.9 ± 7.6 years. Only 2.7% of participants were aged 60 years or older. The mean serum 25-(OH)D concentration was 19.5 ± 6.8 ng/mL. Altered 25-(OH)D levels were found in 93.4% of participants, with 94.0% showing decreased serum 25-(OH)D concentrations and 1.6% displaying deficiency states. Hypovitaminosis D was associated with sex (OR = 2.40; 95% CI: 1.3-5.57; p < 0.05) and sunscreen use (OR = 0.36; 95% IC: 0.13-0.99; p < 0.05). Hypovitaminosis D was almost universal among the apparently healthy university workers studied. The findings suggest that both sex and sunscreen use may independently or jointly contribute to hypovitaminosis D in these individuals. Further studies will be required to clarify this interplay.

Prevention of Melasma During Pregnancy: Risk Factors and Photoprotection-Focused Strategies.

Melasma is a benign but emotionally distressing skin condition that reduces patients' quality of life, with prevalence rates during pregnancy ranging from 36.4% to 75%. Troublingly, up to 30% of cases are reported to persist after delivery, even ten years later. And recurrence and aggravation are common in subsequent pregnancies. This review examines the risk factors and mechanisms associated with melasma during pregnancy and summarized corresponding preventive strategies. We emphasize the critical role of photoprotection, including the use of sunscreens from the first trimester, in reducing the incidence of melasma.

Vitamin D concentration in maternal serum during pregnancy: Assessment in Hokkaido in adjunct study of the Japan Environment and Children's Study (JECS).

Vitamin D is an essential nutrient for maintaining blood calcium and phosphorus levels and controlling bone density. Deficiency in it leads to rickets, osteomalacia, osteoporosis, and various other diseases. Recently, it has gained attention for reportedly reducing the risk of COVID-19 severity. However, there are no reports evaluating pregnant women in the Hokkaido region of Japan. This study aims to elucidate the current status of vitamin D levels in pregnant women in the Hokkaido region. This study measured the serum concentrations of Vitamin D2 and D3 in 206 pregnant women participating in the Japan Environment and Children's Study-Hokkaido sub-cohort at the Hokkaido Regional Center. It analyzed the relationship between these concentrations and the months, seasons, and sunshine hours. The mean maternal age was 31.7 ± 4.7 years, and the mean prepregnancy BMI was 21.0 ± 2.5 kg/m2. Only two women have given birth at least once. Regarding sunscreen use, 65 participants (31.6%) responded "often" or "sometimes." Five women used the supplement containing Vitamin D. The value of 25(OH)D2 was above 1 ng/ml in four of them. The average 25(OH)D3 level was 12.1 ng/ml, with a median of 11.0 ng/ml. Four participants (1.9%) had levels below 5 ng/ml. The highest median of 25(OH)D3 was in July, and the lowest was in April. The concentration of 25(OH)D3 was significantly higher in summer than in winter. A correlation was found between 25(OH)D3 and sunshine hours, with 25(OH)D3 concentrations gradually increasing as sunshine hours increase. It was found that almost all pregnant women in Hokkaido were deficient in vitamin D. It is necessary to implement measures to enhance vitamin D levels in pregnant women to safeguard the health of women and fetuses in Hokkaido.

Knowledge, attitude, and practice of sunscreen use among undergraduate medical students in the College of Medicine, University of Lagos: A cross-sectional study

Knowledge, attitude, and practice of sunscreen use among undergraduate medical students in the College of Medicine, University of Lagos: A cross-sectional study

Efeitos da proteção solar e do manejo de água na fisiologia e produção de pomar de laranja ‘Pêra’ em clima subúmido

Abstract: The risks associated with climate events are the main factors responsible for sweet orange production losses in Brazil. For rainfed citrus cultivation, it is mainly due to soil water deficit, but also to citrus cultivation associated with extreme temperatures. The present study investigated the effects of water management in ‘Pera’ sweet orange orchards under sub-humid climate conditions and application of calcium carbonate-based sunscreen on the plant canopy, aiming to mitigate the effects of abiotic stresses on orchard physiology, production, and irrigation water use efficiency. The experimental design was in randomized blocks in a 3 x 2 factorial scheme. Treatments for water management factor were: full irrigation (100% ETc), irrigation with moderate deficit (65% ETc), and no irrigation; and for sunscreen protection: sunscreen use and no sunscreen. The factors have impacted gas exchange, fruit quality, and orchard yield. There was no isolated effect of soil water management on orchard productivity, but with sunscreen, citrus plants are more resilient based on gas exchange data, mitigating environmental effects (high temperatures and water deficit), resulting in improvements in fruit quality related to total fruit mass in plants grown without irrigation and with 12% increase in orchard productivity, regardless of soil water management. Productivity gains related to sunscreen indicate the need for the use of sunscreen protection regardless of soil water management in the region.

Use Of Micronized Calcium Carbonate-Based Sunscreen on Young European Hazelnut (Corylus Avellana L.) in Commercial Nursery Under Environmental Stress Conditions During the Summer Period

Chile has become one of the main exporters of European hazelnuts in the world, mainly due to favorable edaphoclimatic conditions. Currently, due to the negative effects of climate change, ​​Chile has been suffering recurrent heat waves and droughts, which are damaging the productive efficiency of the European hazelnut. The present research proposes to evaluate the use of a sunscreen composed of micronized calcium carbonate, pinolene and lignosulfonate on young European hazelnut plants growing in a commercial nursery. In this study, the environmental conditions of heat stress observed during the summer months were evaluated. The results show statistically significant differences between treatments, in favor of plants treated with the sunscreen in at least one of the three months of evaluation. Thus, stomatal conductance (gs) showed increases of up to 29% compared to the control treatment, transpiration rate (Tr) increased by up to 25% and the net assimilation rate (an) increased by up to 18% compared to the control treatment without application. The use of sunscreen would increase the gas exchange of young European hazelnut plants, thus providing greater tolerance to conditions of high environmental temperature, promoting an increase in the production of photo-assimilates compared to untreated plants.