Newly planted apple orchards in the USA comprising the highly biennial cultivar, “Honeycrisp”, are prone to flower within the first two years from planting and set fruit. These processes limit canopy development and...Newly planted apple orchards in the USA comprising the highly biennial cultivar, “Honeycrisp”, are prone to flower within the first two years from planting and set fruit. These processes limit canopy development and subsequent yield potential. GA4 + 7 can inhibit floral formation processes of apples. The timing and dose for eliminating return bloom of young “Honeycrisp” trees, however, is unclear. A factorial experimental design to test GA4 + 7 application timing and rate produced significant reductions in return bloom for both factors and their interaction. Treatment responses demonstrated that florigenic processes in “Honeycrisp” occurred early. The most pronounced reduction in return bloom followed the 2-week after full bloom (WAFB) application timing, increasing with increasing rate. The effect on return bloom was progressively diminished over the next two weeks of applications but remained significantly lower than the control. Three successive applications timed one week apart eliminated return bloom of spurs at the highest rate. Both factors and their interaction also significantly reduced return bloom of terminal buds of leaders;in contrast to floral buds on spurs, the response of terminal buds on leaders improved with delayed application timings. Timing exerted a stronger effect than rate on return flowering of the terminal buds of leaders. Leader growth was positively affected by GA4 + 7, the year of application, when three successive applications were made. Tree height, overall growth, expressed as the increase in trunk cross-sectional area, and limb number were also significantly improved by GA4 + 7 but varied in their responses to application timing and rate, and were inconsistent. Overall, successive applications of GA4 + 7 had good efficacy for inhibiting floral initiation of meristems on spurs and terminals while improving the vegetative growth of young “Honeycrisp” trees.展开更多
ETHYLENE RESPONSE FACTOR1(ERF1)is a key component in ethylene signaling,playing crucial roles in both biotic and abiotic stress responses.Here,we demonstrate that ERF1 also has an important role during floral initiati...ETHYLENE RESPONSE FACTOR1(ERF1)is a key component in ethylene signaling,playing crucial roles in both biotic and abiotic stress responses.Here,we demonstrate that ERF1 also has an important role during floral initiation in Arabidopsis thaliana.Knockdown or knockout of ERF1 accelerated floral initiation,whereas overexpression of ERF1 dramatically delayed floral transition.These contrasting phenotypes were correlated with opposite transcript levels of FLOWERING LOCUS T(FT).Chromatin immunoprecipitation(ChIP)assays revealed that ERF1 associates with genomic regions of the FT gene to repress its transcription.ft-10/ERF1RNAi plants showed a similar flowering phenotype to the ft-10 mutant,whereas the flowering of FTox/ERF1ox mimicked that of FTox plants,suggesting that ERF1 acts upstream of FT during floral initiation.Similarly,altered floral transition in ethylene-related mutants was also correlated with FT expression.Further analysis suggested that ERF1 also participates in delay in flowering-time control mediated by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid.Thus,ERF1 may act as a negative modulator of flowering-time control by repressing FT transcription in Arabidopsis.展开更多
文摘Newly planted apple orchards in the USA comprising the highly biennial cultivar, “Honeycrisp”, are prone to flower within the first two years from planting and set fruit. These processes limit canopy development and subsequent yield potential. GA4 + 7 can inhibit floral formation processes of apples. The timing and dose for eliminating return bloom of young “Honeycrisp” trees, however, is unclear. A factorial experimental design to test GA4 + 7 application timing and rate produced significant reductions in return bloom for both factors and their interaction. Treatment responses demonstrated that florigenic processes in “Honeycrisp” occurred early. The most pronounced reduction in return bloom followed the 2-week after full bloom (WAFB) application timing, increasing with increasing rate. The effect on return bloom was progressively diminished over the next two weeks of applications but remained significantly lower than the control. Three successive applications timed one week apart eliminated return bloom of spurs at the highest rate. Both factors and their interaction also significantly reduced return bloom of terminal buds of leaders;in contrast to floral buds on spurs, the response of terminal buds on leaders improved with delayed application timings. Timing exerted a stronger effect than rate on return flowering of the terminal buds of leaders. Leader growth was positively affected by GA4 + 7, the year of application, when three successive applications were made. Tree height, overall growth, expressed as the increase in trunk cross-sectional area, and limb number were also significantly improved by GA4 + 7 but varied in their responses to application timing and rate, and were inconsistent. Overall, successive applications of GA4 + 7 had good efficacy for inhibiting floral initiation of meristems on spurs and terminals while improving the vegetative growth of young “Honeycrisp” trees.
基金providing the ocfi7jD/e mutant acs7/2/4/5/6/7/9/11(CS16651),eto2(CS8059),cfr7-7(CS8057),sis1-1(CS3874),and ERFlox(CS6142 and CS6143)also thank Chengbin Xiang(University of Science and Technology of China)for providing ERF7-related materials+1 种基金This study was supported by the Yunnan Fundamental Research Projects(2019FA010 and 2019FB029)the Strategic Leading Science&Technology Programme(XDA24030301)of the Chinese Academy of Sciences.
文摘ETHYLENE RESPONSE FACTOR1(ERF1)is a key component in ethylene signaling,playing crucial roles in both biotic and abiotic stress responses.Here,we demonstrate that ERF1 also has an important role during floral initiation in Arabidopsis thaliana.Knockdown or knockout of ERF1 accelerated floral initiation,whereas overexpression of ERF1 dramatically delayed floral transition.These contrasting phenotypes were correlated with opposite transcript levels of FLOWERING LOCUS T(FT).Chromatin immunoprecipitation(ChIP)assays revealed that ERF1 associates with genomic regions of the FT gene to repress its transcription.ft-10/ERF1RNAi plants showed a similar flowering phenotype to the ft-10 mutant,whereas the flowering of FTox/ERF1ox mimicked that of FTox plants,suggesting that ERF1 acts upstream of FT during floral initiation.Similarly,altered floral transition in ethylene-related mutants was also correlated with FT expression.Further analysis suggested that ERF1 also participates in delay in flowering-time control mediated by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid.Thus,ERF1 may act as a negative modulator of flowering-time control by repressing FT transcription in Arabidopsis.
