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Developmental transitions in plants require adequate carbon resources, and organ abscission often occurs due to competition for carbohydrates/assimilates. Physiological studies have indicated that organ abscission may be activated by sucrose deprivation; however, an underlying regulatory mechanism that links sucrose transport to organ shedding has yet to be identified. Here, we report that transport of sucrose and the phytohormone auxin to petals through the phloem of the abscission zone (AZ) decreases during petal abscission in rose (Rosa hybrida), and that auxin regulates sucrose transport into the petals. Expression of the sucrose transporter RhSUC2 decreased in the AZ during rose petal abscission. Similarly, silencing of RhSUC2 reduced the sucrose content in the petals and promotes petal abscission. We established that the auxin signaling protein RhARF7 binds to the promoter of RhSUC2, and that silencing of RhARF7 reduces petal sucrose contents and promotes petal abscission. Overexpression of RhSUC2 in the petal AZ restored accelerated petal abscission caused by RhARF7 silencing. Moreover, treatment of rose petals with auxin and sucrose delayed ethylene-induced abscission, while silencing of RhARF7 and RhSUC2 accelerated ethylene-induced petal abscission. Our results demonstrate that auxin modulates sucrose transport during petal abscission, and that this process is regulated by a RhARF7-RhSUC2 module in the AZ.

cn). † These authors contributed equally to this work. SUMMARYThe timing of plant organ abscission is modulated by the balance of two hormones, ethylene and auxin, while the mechanism of organ shedding depends on the loss of middle lamella pectin in the abscission zone (AZ). However, the mechanisms involved in sensing the balance of auxin and ethylene and that affect pectin degradation during abscission are not well understood. In this study, we identified two members of the APETALA2/ethylene-responsive factor (AP2/ERF) transcription factor family in rose (Rosa hybrida), RhERF1 and RhERF4 which play a role in petal abscission. The expression of RhERF1 and RhERF4 was influenced by ethylene and auxin, respectively. Reduced expression of RhERF1 or RhERF4 was observed to accelerate petal abscission. Global expression analysis and real-time PCR assays revealed that RhERF1 and RhERF4 modulate the expression of genes encoding pectin-metabolizing enzymes. A reduction in the abundance of pectin epitopes was detected in the AZs of RhERF1 and RhERF4-silenced plants by immunofluorescence microscopy analysis. In addition, RhERF1 and RhERF4 were shown to bind to the promoter of the pectin-metabolizing gene b-GALACTOSIDASE 1 (RhBGLA1), and reduced expression of RhBGLA1 delayed petal abscission. We conclude that during petal abscission, RhERF1 and RhERF4 integrate and coordinate ethylene and auxin signals to modulate pectin metabolism, in part by regulating the expression of RhBGLA1.

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Purpose The purpose of this paper with pork as a case is to analyze Chinese consumer preference and demand for traceable food attributes, in order to provide a useful reference for Chinese Government in developing the safe food market and preventing food safety risks. Design/methodology/approach This research surveyed 1,380 consumers in seven pilot cities that designated by the Chinese Ministry of Commerce for the construction of a meat and vegetable circulation traceability system. A choice-based conjoint analysis and multinomial logit model were used to study consumer preferences and demand for traceable pork attributes. Findings The results demonstrated that certification of traceable information was the most important characteristic, followed by appearance and traceable information. Significant heterogeneity was obtained in consumer preferences for the attributes of traceable pork. Also, consumers’ preferences for traceable attributes were memorably influenced by age, education level, and income level. Social implications Based on these results, the government should encourage and support the production of traceable food with different certification types and different traceability levels. Meanwhile, the development of food traceability systems should be combined with a quality certification labeling system. Originality/value This study extends the applicability of the setting of traceable food attributes and levels in China, and it will improve Chinese food traceability systems through multilateral cooperation.

Effects of sublethal concentrations (LC25) of six insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on fecundity and wing dimorphism of the green peach aphid, Myzus persicae (Sulzer), were studied both under laboratory and greenhouse conditions. In the laboratory, aphid reproduction reduced by 44.29% and 54.01% when rotenone and abamectin treatments were applied at sublethal dose, respectively, and sublethal fenvalerate application resulted in markedly lower average reproduction per female per day compared with control. Reproductive duration of aphid treated with abamectin significantly decreased by 44.19%. But in the greenhouse, there were no evident differences in the aphid fecundity and reproductive duration between treatments and control. Life‐table parameters also demonstrated that the six insecticides at sublethal doses did not stimulate the aphid reproductive potential. In the laboratory, after being exposed to sublethal doses of imidacloprid and fenvalerate, the proportions of alate progeny in aphid progeny were significantly higher than that of the control. In the greenhouse, percentages of alate offspring from the mother aphids treated with imidacloprid, fenvalerate and abamectin increased pronouncedly compared with control. Mortality rates of offspring in the nymphal stages from adults treated with insecticides revealed no significant changes between laboratory and greenhouse. The developmental time in days of the offspring varied in all treatments. Mechanisms of insecticide‐induced resurgence are discussed.

BackgroundIn China, the problems of population aging and empty nesting have become important issues which will affect the social stability and economic development. The aim of this study was to explore the health promoting lifestyles and influencing factors among empty nesters and compare with non-empty nesters to find out their differences, so as to provide a scientific evidence for people to formulate health management strategies for elderly.MethodsA cross-sectional survey which used a stratified random cluster sampling method, was conducted among 500 elders in six districts of Taiyuan, China, there were 288 empty nesters and 212 non-empty nesters. The general information and health- promoting lifestyles were investigated by using the self-made General Information Questionnaire and Health Promoting Lifestyle Scale(HPLP). Two-sample t-test and Chi-square test were used to compare the sociodemographic factors, HPLP scores of empty nesters to non-empty nesters; Multiple stepwise linear regression was performed to estimate influencing factors related to the HPLP of empty nesters and non-empty nesters.ResultsThe current findings showed that there were differences between the empty nesters and non-empty nesters in gender, resident, marital status, education and income, self-care ability, source of income, relationship with spouse and social activities (P < 0.05). Empty nesters were mostly male, married, had a higher education level, self-care ability and income and lived in urban compared with non-empty nesters. The health promoting lifestyles of the elderly in this survey were in the medium level, the highest score for all dimensions in both groups was in nutrition, whereas health responsibility was executed worst. The HPLP and six subscales scores of the empty nesters were higher than non-empty nesters, there were significant differences in total score of HPLP, self-realization and health responsibility (P < 0.01). Multiple regression analysis showed that the main predictive factors for the empty nesters were education, self-care ability and resident, whereas the main predictive factors for the non-empty nesters were parents-child relationship, source of income and age; social activity was the common factor for two group.ConclusionThe health promoting lifestyles of the empty nesters was better than that of the non-empty nesters. Health responsibility, interpersonal relations and stress management were key dimensions to be improved. Except social activity, education, self-care ability and resident were the unique influencing factors of health-promoting lifestyles for empty nesters, while the parents-child relationship, income and age were unique factors for non-empty nesters. The main target of Intervention strategy for elderly health promoting lifestyles should be the enhance of health responsibility, interpersonal relations and stress management by improving social activities, parent-child relationship, education and income of elderly.