Quantitative trait loci identification reveals zinc finger protein CONSTANS-LIKE 4 as the key candidate gene of stigma color in watermelon(Citrullus lanatus)

Stigma color is a critical agronomic trait in watermelon that plays an important role in pollination.However,there are few reports on the regulation of stigma color in watermelon.In this study,a genetic analysis of the F2 population derived from ZXG1553(P1,with orange stigma)and W1-17(P2,with yellow stigma)indicated that stigma color is a quantitative trait and the orange stigma is recessive compared with the yellow stigma.Bulk segregant analysis sequencing(BSA-seq)revealed a 3.75 Mb segment on chromosome 6 that is related to stigma color.Also,a major stable effective QTL Clqsc6.1(QTL stigma color)was detected in two years between cleaved amplified polymorphic sequencing(CAPS)markers Chr06_8338913 and Chr06_9344593 spanning a~1.01 Mb interval that harbors 51 annotated genes.Cla97C06G117020(annotated as zinc finger protein CONSTANS-LIKE 4)was identified as the best candidate gene for the stigma color trait through RNA-seq,quantitative real-time PCR(qRT-PCR),and gene structure alignment analysis among the natural watermelon panel.The expression level of Cla97C06G117020 in the orange stigma accession was lower than in the yellow stigma accessions with a significant difference.A nonsynonymous SNP site of the Cla97C06G117020 coding region that causes amino acid variation was related to the stigma color variation among nine watermelon accessions according to their re-sequencing data.Stigma color formation is often related to carotenoids,and we also found that the expression trend of ClCHYB(annotated asβ-carotene hydroxylase)in the carotenoid metabolic pathway was consistent with Cla97C06G117020,and it was expressed in low amounts in the orange stigma accession.These data indicated that Cla97C06G117020 and ClCHYB may interact to form the stigma color.This study provides a theoretical basis for gene fine mapping and mechanisms for the regulation of stigma color in watermelon.

Saffron(Crocus sativus L.) stigmas as a potential natural additive to improve oxidative stability attributes of sunflower(Helianthus annuus L.) oil stored under different conditions

The aim of our study was to explore the antioxidant potential of Moroccan saffron stigmas(SS) and examine their performance as a natural antioxidant in enhancing the stability and quality properties of edible sunflower oil(SO), with a focus on understanding the critical importance of edible oil stability for predicting quality deterioration during storage. Bearing this in mind, our research was designed to compare the efficacy of three concentrations of dried SS(at 0.2%, 0.3%, and 0.6%) against tocobiol(a synthetic antioxidant) as a positive control(at 0.3% concentration). This comparison was conducted under three distinct storage conditions namely accelerated ageing(60 ℃), exposure to light at ambient temperature, and darkness, to evaluate their impact on preventing severe oxidation and extending oil shelf-life. Oxidation state evolution was evaluated through peroxide value(PV), free fatty acid(FFA), anisidine value(p-AV), K_(270)value(conjugated trienes), total oxidation index(TOTOX), iodine value(IV), and fatty acid composition(FA). Our results revealed notable differences in stability tracking parameters. Specifically, these parameters were higher in samples stored under accelerated conditions, followed by the samples stored in ambient light, while those stored in darkness showed the highest stability among the three storage conditions. Supplementation of sunflower oil with SS and tocobiol significantly enhanced its oxidation stability. Notably, SS exhibited exceptional effectiveness in stabilizing sunflower oil regardless of SS dose, with the highest efficacy observed at 0.6%. This was evidenced by the slower rate of oxidation parameters under various storage conditions, highlighting a superior antioxidant activity compared to both the non-enriched oil and tocobiol-enriched oil. Furthermore, saffron stigmas, used as a natural supplement,contributed to the preservation of polyunsaturated fatty acids, indicating its potential as a robust source of natural antioxidants in sunflower oil. These attributes position SS as a promising alternative to synthetic antioxidants, offering opportunities to enhance the nutritional quality and extend edible oil shelf-life.

Assessing the current situation and the influencing factors affecting perceived stigma among older patients after leukemia diagnosis

BACKGROUND Psychological problems are becoming increasingly prominent among older patients with leukemia,with patients potentially facing stigmatization after diagnosis.However,there is limited research on the stigma experienced by these patients and the factors that may contribute to it.AIM To investigate the stigma faced by older patients after being diagnosed with leukemia and to analyze the potential influencing factors.METHODS A retrospective analysis was conducted using clinical data obtained from questionnaire surveys,interviews,and the medical records of older patients with leukemia admitted to the Hengyang Medical School from June 2020 to June 2023.The data obtained included participants’basic demographic information,medical history,leukemia type,family history of leukemia,average monthly family income,pension,and tendency to conceal illness.The Chinese versions of the Social Impact Scale(SIS),Perceived Social Support Scale(PSSS),Self-Rating Anxiety Scale(SAS),and Self-Rating Depression Scale(SDS)were used to assess indicators related to stigma,social support,and mental health status.We used Pearson’s correlation coefficient to analyze the strength and direction of the relationship between the scores of each scale,and regression analysis to explore the factors related to the stigma of older patients with leukemia after diagnosis.RESULTS Data from 120 patients with leukemia aged 65-80 years were analyzed.The total score on the SIS and PSSS was 43.60±4.07 and 37.06±2.87,respectively.The SAS score was 58.35±8.32 and the SDS score was 60.58±5.97.The stigma experienced by older leukemia patients was negatively correlated with social support(r=-0.691,P<0.05)and positively correlated with anxiety and depression(r=0.506,0.382,P<0.05).Age,education level,smoking status,average monthly family income,pension,and tendency to conceal illness were significantly associated with the participants’level of stigma(P<0.05).Age,smoking status,social support,anxiety,and depression were predictive factors of stigmatization among older leukemia patients after diagnosis(all P<0.05),with a coefficient of determination(R2)of 0.644 and an adjusted R2 of 0.607.CONCLUSION Older patients commonly experience stigmatization after being diagnosed with leukemia.Factors such as age,smoking status,social support,and psychological well-being may influence older patients’reported experience of stigma.

Tendency to Avoid Physical Activity and Sport:Associations with Weight Stigma,and Psychological Distress in a Two-Wave Longitudinal Study

Background:Physical inactivity is a major public health problem worldwide that results in physical and mental health problems.One major issue for physical inactivity is weight stigma(WS),especially perceived WS,which could lead to a tendency to avoid physical activity(PA).To better understand the association between perceived WS and PA,knowledge of the likely mediators in this association such as weight bias internalization(WBI)and psychological distress were investigated in the present study.Methods:Using a two-wave longitudinal study and convenient sampling,388 Taiwan residents participants(55%females;mean age=29.7 years[SD±6.3])completed two surveys six months apart.Body mass index(BMI),Perceived Weight Stigma Scale(PWSS),Weight Bias Internalization Scale(WBIS),Depression,Anxiety,Stress Scale(DASS-21),and Tendency to Avoid Physical Activity and Sport Scale(TAPAS)were assessed.Results:A mediation model controlling for age,gender,and BMI with 5000 bootstrapping resamples was performed.Perceived WS exerted significant direct effects on WBI(β=0.25;p<0.001),psychological distress(β=0.15;p=0.003),and tendency to avoid PA(β=0.10;p=0.027);WBI exerted a significant direct effect on tendency to avoid PA(β=0.47;p<0.001).Standardized indirect effects of WBI and psychological distress on the association between perceived WS and tendency to avoid PA were 0.12 and 0.01,respectively.Conclusion:Given the direct association of perceived WS on the tendency to avoid PA and the mediating role of WBI in this association,interventions addressing perceived WS and WBI may contribute to promoting PA.Therefore,health interventionists(both when planning and executing PA programs)need to consider weight stigmawhen encouraging physical activity.

Effects of Alexithymia to Stigma of Patients with Lymphedema

BACKGROUND: Secondary lymphedema is one of the common complications after malignant tumor surgery. It is a chronic and complex disease. Once lymphedema occurs, there will be discomfort such as limb swelling, pain, numbness and tension, which will eventually lead to changes in the appearance of the affected limb and will seriously affect the quality of life and require lifelong treatment and psychosocial support. This study investigated the current situation of stigma and alexithymia in patients with lymphedema, and discussed the impact of alexithymia on stigma in patients with lymphedema. AIMS: To understand the current situation of stigma and alexithymia in patients with lymphedema, and to analyze the influence of alexithymia on stigma. METHODS: 195 patients with lymphedema in a hospital were selected by convenient sampling. General information questionnaire, Toronto Alexithymia Scale and social impact scale were used to investigate respectively, to study the general situation, stigma and alexithymia of the respondents. RESULTS: The results showed that the total score of stigma in 195 patients with lymphedema was (60.36 ± 11.08), and the total score of alexithymia was (56.53 ± 8.43). Multiple linear regression analysis showed that alexithymia and family relationship were the influencing factors of stigma in patients with lymphedema. CONCLUSIONS: The patients with lymphedema have obvious stigma, and alexithymia and family relationship are the influencing factors.

Analysis of the Current Situation of Stigma Among Elderly Hemodialysis Patients and its Influencing Factors

Objective:To understand the current situation of stigma among elderly hemodialysis patients and to analyze its influencing factors.Methods:Convenience sampling was used to select 242 elderly patients undergoing hemodialysis in one of the two tertiary hospitals in Mianyang City.The survey was carried out from December 2022 to March 2023,with the Basic Information Questionnaire,the Social Influence Scale,and the Collaborative Social Support Scale.All influencing factors were analyzed by correlation analysis,univariate analysis,and multiple linear regression.Results:The average stigma score among elderly hemodialysis patients was 72.94±9.58,and the influencing factors of stigma among elderly hemodialysis patients were determined to be social support and economic status(P<0.05).Conclusion:The occurrence of stigma among elderly hemodialysis patients was at a moderate to high level,and the influencing factors were mainly economic status and social support.To reduce the occurrence of stigma in elderly hemodialysis patients,appropriate economic support from families and social support from medical personnel are needed.

Analysis of the Current Status and Influencing Factors of Family Members’Collateral Stigma in Schizophrenia Patients

Objective: To investigate the associated collateral stigma of the family members of schizophrenia patients and analyze its current status and influencing factors. Methods: The Link Depreciation-Discrimination Perception Scale was used to investigate the status quo of the associated stigma of the family members of 169 schizophrenia patients diagnosed in 4 hospitals in a certain province. The results of the investigation were analyzed and summarized. Results: The detection rate of stigma associated with the family members of schizophrenia patients was 72.78%, with a score of 28.41 ± 3.92 points. The main influencing factors were the family member’s education level, the patient’s illness duration, the family member’s occupation, and the family-patient relationship. Conclusion: The detection rate of stigma associated with schizophrenia was relatively high. This requires increased attention and appropriate nursing intervention.

Psychiatrists’occupational stigma conceptualization,measurement,and intervention:A literature review

Psychiatrists require frequent contact with and treatment of patients with mental illnesses.Due to the influence of associative stigma,psychiatrists may also be targets of stigma.Occupational stigma warrants special consideration because it significantly affects psychiatrists'career advancement,well-being,and their patients’health.Given that there is no complete summary of this issue,this study reviewed the existing literature on psychiatrists'occupational stigma to clearly synthesize its concepts,measurement tools,and intervention strategies.Herein,we emphasize that psychiatrists’occupational stigma is a multifaceted concept that simultaneously encompasses physically,socially,and morally tainted aspects.Currently,standardized methods to specifically measure psychiatrists’occupational stigma are lacking.Interventions for psychiatrists’occupational stigma may consider the use of protest,contact,education,comprehensive and systematic methods,as well as the use of psychotherapeutic approaches.This review provides a theoretical basis for the development of relevant measurement tools and intervention practices.Overall,this review seeks to raise public awareness of psychiatrists'occupational stigma,thereby promoting psychiatric professionalism and reducing its stigma.

QTL Analysis of Traits Related to Melon Stigma and Ovary Size

The melon varieties MR-1 and M4-7 were used as the parent materials to produce hybrids.A total of 170 F2 individuals were used as the mapping population to construct a genetic linkage map.In this study,240 cleaved amplified polymorphism sequence(CAPS)molecular markers were developed,and 105 of which showed polymorphism between parents.The map contained 105 markers grouped into 12 linkage groups,spanning a total length of 1998.85 cM,with an average length of 19.04 cM between markers.The composite interval mapping(CIM)method was used to detect QTLs related with melon stigma and ovary traits:stigma longitudinal diameter(STLD),stigma transverse diameter(STTD),stigma weight(STW),ovary longitudinal diameter(OLD),and ovary transverse diameter(OTD).A total of nine QTLs were identified:six for stigma size and three for ovary size.A total of six loci were detected for stigma size,which included two loci for stigma longitudinal diameter,two loci for stigma transverse diameter,and two loci for stigma weight.The major effective locus regulating stigma transverse diameter was qSTTD-9-1.A total of three loci were identified for ovary size traits,including one locus for ovary longitudinal diameter and two loci for ovary transverse diameter.

Current Status of Research on Pollen Vitality and Stigma Receptivity of Wuren Walnut(Juglans sigillata)in Guizhou Province

Wuren walnut is a unique germplasm resource of Juglans sigillata in Guizhou Province,named after its purple and black seed coat.It is a typical medicinal and edible plant with high nutritional value and good taste compared with ordinary walnut.The color of its inner seed coat is different from that of ordinary walnut,which is mostly light yellow.Wuren walnut has great market potential for development.To lay a theoretical foundation for the future breeding of improved varieties,pollination tree configuration,and hybrid breeding of Wuren walnut in Guizhou Province,this paper summarized the current research status of pollen vitality and stigma acceptability of Guizhou Wuren walnut in recent years,and looked forward to future research and application.

Double Tragedy: Examining the Effects of Mental Health Stigma on Help Seeking Behaviour among Deaf People in Ghana

Background: Globally, mental health is recognized as one of the major public health issues, and mental health stigma is one of the main barriers to mental healthcare. While several studies have been conducted on the stigma associated with mental health, very little is known about the mental health stigma experienced by deaf persons with mental health conditions in Ghana. This study examines the experiences of double stigmatization by deaf people with mental health conditions in Ghana. Methodology: A descriptive, mixed method data collection was used for seventy-nine (79) participants. The paper presents findings from the only qualitative component of the study. Results: The findings from the study showed that deaf people with mental illness experienced double stigma, namely being stigmatized for being deaf and for having mental illness. This hindered access to mental health services for deaf people with mental health condition. Conclusion: Deaf people with mental health conditions experience double stigmatization which discourages them from seeking professional psychiatric care. This implies that efforts to reduce mental health stigma and create awareness on deafness should be improved upon. It is recommended that, in view of the impact of stigma on the provision and use of mental health care services, strategies to improve access to mental health care, should seriously consider concerns about stigma.

Correlation between Stigma Characteristics and Outcrossing Rate of Five Photo-thermo Sensitive Genic Male Sterile(PTGMS) Rice Lines

[Objective] This study aimed to investigate the correlation between stigma characteristics and outcrossing rate of photo-thermo sensitive genic male sterile（PTGMS） rice lines. [Method] The stigma exsertion rate, stigma size and stigma vitality of Chuang 5S, Yun 9S, Peiai 64 S, P88 S and Y58 S were analyzed. Using R608 as a male parent, outcrossing rate of these five PTGMS lines was determined. [Result]There were differences in stigma exsertion rate, stigma size and stigma vitality among five PTGMS lines. P88 S exhibited the best stigma characteristics and relatively strong stigma vitality, with the stigma exsertion rate of 95.94%, stigma vitality coefficient of 2.71, outcrossing rate of 84.02% in the field. Peiai 64 s had the minimum stigma length（2.41 mm） and stigma width（1.10 mm） and the weakest stigma vitality, with the stigma exsertion rate of 93.04%, outcrossing rate of 65.47%. Yun 9S,Y58 S and Chuang 5S displayed medium stigma characteristics, among which Yun9 S exhibited higher outcrossing rate than other two PTGMS lines. Correlation analysis showed that stigma exsertion rate, stigma length, stigma width, stigma area and stigma volume were significantly correlated to outcrossing rate（P〈0.05）, with correlation coefficients of 0.897, 0.934, 0.934, 0.939 and 0.937, respectively. However,there was no significant correlation between stigma vitality coefficient and outcrossing rate. [Conclusion] Based on stigma characteristics of five PTGMS lines, auxiliary pollination measures should be adopted reasonably to save production costs and improve hybrid rice seed yield.

Pistillate Flower Development and Stigma Receptivity of Euphorbia pulcherrima

Objective] This study aimed to investigate the relationship between pistil-late flower developmental morphology and stigma receptivity in Euphorbia pulcherri-ma. [Method] One-year-old adult plants of E. pulcherrima cultivar ‘Mil enium’ were used as experimental materials to analyze pistil ate flower development process by macroscopic and scanning electron microscope （SEM） observation. Stigma receptivity was detected with benzidine-hydrogen peroxide method and in vivo pol en germina-tion method. [Result] The pistil ate flower development process of E. pulcherrima was consisted of columnar stigma phase, stigma lobe slightly opening phase, Y-shape stigma lobe phase, inverse V-shaped stigma lobe phase and stigma curling phase. Pistil ate flower development and stigma receptivity of E. pulcherrima exhibit-ed certain correlation. The stigma receptive period lasted from stigma lobe slightly opening phase to inverse V-shaped stigma lobe phase; inverse V-shaped stigma lobe phase was appropriate for pol ination, lasting for 3-5 d, with V-shaped stigma lobe and a large amount of exudates on stigma surface according to SEM obser-vation. Stigma receptivity of E. pulcherrima detected with benzidine-hydrogen perox-ide method was consistent with that detected in vivo pol en germination method. [Conclusion] ln breeding practice, the optimal pol ination period of E. pulcherrima can be determined based on the developmental morphology of pistil ate flower.

THE SECRETORY STIGMAS IN POPULUS: DEVELOPMENT, CYTOCHEMISTRY, ULTRASTRUCTURE AND THEIR RELATION TO INTERSECTIONAL INCOMPATIBILITY *

The stigmas of five species, Populus euphratica Oliv., P. alba L., P. simonii Carr., P. lasiocarpa Oliv. and P. nigra L. have been studied. Scanning electron microscopy re veals that exudates are present in the intercellular spaces, in the clefts between the multicel lular papillae and on the receptive surface. Release and movement of exudates can be visual ized when the fresh stigmas are stained with sudan Ⅲ and auramine O. Paraffin and semi thin resin sections of stigmas after glutaraldehyde osmium fixation evidence the lipidic nature of the exudates. Transmission electron microscopy reveals the glandular features of the stigmatic papillae cells, such as abundance of rough and smooth endoplasmic reticulum, polyribosomes, and well developed dictyosomes with secretory vesicles. Pellicle and epicuticular lamellate layers which have been considered as typical features of the dry type stigmas are also present in the species where stigmas appear extremely wet. It is concluded that stigmas in all of the five species are secretory at the receptive stage. Well developed generative and sperm cells were observed in the pollen tubes penetrating through the deep layers of the stigmatic tissue in the reciprocal crosses between P. euphratica and P. simonii, which indicated that there is no significant barrier in the stigma.

Preliminary Discussion on Stigma Vitality of Sterile Line Rong 18A and Its Application in Seed Production

Rong 18A is an Indica three-line sterile line bred with M5B×D Xing B, and has the characteristics of stable sterility, high outcrossing rate, good combining ability and good quality. With Rong 18A as an experimental material and Ⅱ-32A, Jin 23A and Gang46 A as the CK materials, a seed setting rate estimation method by daily pollination was used for measuring its stigma vigor, to comparatively analyze the decreasing rates and lasting time of stigma vigor of various materials under natural condition. According to experimental results and combining with field breeding practice, the application of stigma vigor of sterile lines on hybrid rice seed production was discussed.

Preliminary Study on Inheritance of Stigma Exertion in Wheat Thermo-photo Sensitive Genic Male Sterile Line

Stigma exertion is one of the key factors for improving the outcrossing ability of wheat thermo-photo sensitive genic male sterile（TPSGMS） line. A DH population derived from K239S/K92 S was constructed to investigate the inheritance of stigma exertion. K239 S and K92 S are TPSGMS lines with higher and lower stigma exertion rates（SER）, respectively. The SERs of parents, reciprocal crosses and the DH population were evaluated for two consecutive years. The results showed that no significant difference was observed in SER between F1 s of K239S/K92 S and K92S/K239 S,implying that stigma exertion was a trait controlled by nuclear gene（s）. In the DH population, the segregation of low and high SERs fitted to a ratio of 3 ∶1 by Chisquare test, suggesting that the stigma exertion of K239 S was controlled by one pair of recessive genes. In addition, the effects of temperature and humidity on the expression of stigma exertion were also discussed.

Study on Pollen Viability and Stigma Receptivity of Very Later-ripening ‘Dongxing' Apricot

[Objective] The primary aims of this study were to understand the characteristic of floralorgan development in ‘Dongxing＇, and analyze its differences with other apricot varieties. [Method] Floral organ morphology, pollen quantity, pollen viability and stigma receptivityof ‘Dongxing＇ and other apricot varieties were observed and measured. [Result] The ratio between the medium style and long style of‘Dongxing＇ was 82.4%, and the ratio of pistillode was lower than that in the other apricot varieties. Its pollen quantity was 32 183.2 grains per flower, and was fewer than the others. The pollen germination of ‘Dongxing＇ in optimum medium（1% agar ＋15% sucrose ＋ 0.01% boric acid） was 53.0%, i.e. its pollen viability was low. The pollen viability increased at first and then decreased following the period of the bud stage to flowering stage, and pollen viability reached maximum value at the 1st d after flowering. Meanwhile the stored pollen viability continuously decreased with the extension of storage time, and pollen viability of the both vivo or vitro stored was decreased to the half of the maximum value at the 3rdd after flowering or storage.The stigma receptivity of ‘ongxing＇ enhanced at first then weakened, maximum stigma receptivity was found at the period of 2 h to 4 h after flowering. The optimum time for artificial pollination was 1 h to 8 h after flowering and it was shorter than the other apricot varieties was. [Conclusion] The ratio between the medium style and long style of ‘Dongxing＇ was higher than the other apricot varieties, while the pollen viability of ‘Dongxing＇ on the contrary. Its pollen viability reached maximum value at the 1st d after flowering and the optimum time for artificial pollination was1 h to 8h after flowering.

Care Plan for Reducing Stigma in Cancer Disease

Purpose: Disease-related Stigma is negative emotions, attitudes, stereotypes, and beliefs about diseases. Cancer is one of the diseases that can be exposed to stigma. Regarding the effects of stigma on the quality of life;admission and adherence to treatment, and considering stigma as a barrier to health promotion and cancer screening, the aim of this study was to provide a care plan for reducing stigma in cancer. Methods: This research was carried out during three phases of qualitative, quantitative studies and a review of the literature. The qualitative phase was conducted by conventional content analysis to find effective factors on the reduction of stigma through face to face semi-structured interviews. The quantitative phase was a cross-sectional descriptive study to measure the level of stigma. By using both quantitative and qualitative findings, and a review of the literature, a comprehensive care plan to reduce stigma in families with cancer patients was developed. Results: The results showed two categories of data;1) reducing stigma at the individual or family level which needs increasing awareness, teaching coping skills, and support, as well as counseling;and 2) stigma reduction at the community level and policy rules which involve public education and cultural changes. Conclusion: Implementation of a care plan for reducing stigma can increase the physical and psychological health outcomes of people influenced by cancer, and at the community level, improves the attitude toward cancer and the success of screening programs, and ultimately reduces disability and mortality of the disease.

The Influence of Stigma on People with Mental Illness

People with mental illness have not only struggled with the psychological and physical symptoms of the disease but also suffered from social discrimination and prejudice.[1]This article expresses the negative impact of mental illness stigma on the stigmatized group through the study of previous literature.The purpose of this article is to improve the public’s stereotypes and prejudices of people with mental illness,so as to provide a basis for researchers to identify effective de-stigmatization strategies.

Enclosed stigma contributes to higher spikelet fertility for rice(Oryza sativa L.) subjected to heat stress

With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase pollen reception and promote female reproductive success.The aim of this study was to investigate the role of stigma exsertion on spikelet fertility at high temperatures.Five rice cultivars(Liangyoupeijiu, Shanyou 63, Huanghuazhan, Nagina 22, and IR64) with differing degrees of stigma exsertion were cultivated and exposed to high temperature at anthesis.Heat-tolerant cultivars did not always show a high percentage of spikelets with exserted stigmas, and vice versa.Irrespective of the presence of more pollen grains on exserted stigmas, spikelets with exserted stigmas did not show greater spikelet fertility than spikelets with fewer exserted stigmas or hidden stigmas under heat stress.GA3 application augmented the percentage of spikelets with exserted stigmas;however, it did not increase spikelet fertility under heat stress.Spikelet fertility of whole panicles was negatively correlated with the percentage of spikelets with exserted stigmas, but positively with that with hidden stigmas.Viability of the hidden stigmas was less reduced than that of exserted stigmas under heat stress, suggesting that hidden stigmas have an advantage in maintaining viability.Heat stress delayed anther dehiscence and reduced the viabilities of both exserted stigmas and pollens, thereby causing low spikelet fertility.Together, these results suggest that high spikelet fertility does not depend on stigma exsertion and that enclosed stigma generally contributes to higher spikelet fertility and heat tolerance under high-temperature conditions during flowering in rice.