Erratum

Nighttime temperature treatment of fruit clusters of 'Ald Queen' grapes during maturation and its effects ofn the sldn color and abscisic acid contentVitis 46 (4), 208-209 (2007

Nighttime temperature treatment of fruit clusters of ‘Aki Queen’ grapes during maturation and its effect on the skin color and abscisic acid content

Research Note

Effect of short-term temperature treatment to clusters on anthocyanin and abscisic acid content in the peel of 'Aki Queen' grape

The effect of short-term low and high temperature treatment to clusters before and after the onset of color development on anthocyanin and abscisic acid (ABA) content in the peel of 'Aki Queen' (Vitis labruscana L.), a tetraploid grape cultivar with red peel was investigated. Grape clusters were exposed to different temperature conditions, either from the beginning of the berry softening to the onset of color development, 47 to 56 days after full bloom (DAFB), or from the onset of color development onwards for 10 days, 56 to 66 DAFB. Low-temperature (2-5 °C lower than control) treatments in both, 47 to 56 DAFB and 56 to 66 DAFB had the tendency to increase anthocyanin concentration and the concentration in the peel was higher than that in the control. The difference in the ABA content after low and high temperature treatment in the 47 to 56 DAFB suggests that temperature from the beginning of berry softening to the onset of color development might affect the ABA content of the peel. On the other hand, treatment from the onset of color development onwards for 10 days might affect the anthocyanin concentration, but the effect on ABA content is relatively low. These results suggest that temperature-dependent accumulation of anthocyanin during maturation correlate with ABA content at the onset of color development in 'Aki Queen' grape.

Transcriptome profile analysis of flowering molecular processes of early flowering trifoliate orange mutant and the wild-type [Poncirus trifoliata (L.) Raf.] by massively parallel signature sequencing

<p>Abstract</p> <p>Background</p> <p>After several years in the juvenile phase, trees undergo flowering transition to become mature (florally competent) trees. This transition depends on the balanced expression of a complex network of genes that is regulated by both endogenous and environmental factors. However, relatively little is known about the molecular processes regulating flowering transition in woody plants compared with herbaceous plants.</p> <p>Results</p> <p>Comparative transcript profiling of spring shoots after self-pruning was performed on a spontaneously early flowering trifoliate orange mutant (precocious trifoliate orange, <it>Poncirus trifoliata</it>) with a short juvenile phase and the wild-type (WT) tree by using massively parallel signature sequencing (MPSS). A total of 16,564,500 and 16,235,952 high quality reads were obtained for the WT and the mutant (MT), respectively. Interpretation of the MPSS signatures revealed that the total number of transcribed genes in the MT (31,468) was larger than in the WT (29,864), suggesting that newly initiated transcription occurs in the MT. Further comparison of the transcripts revealed that 2735 genes had more than twofold expression difference in the MT compared with the WT. In addition, we identified 110 citrus flowering-time genes homologous with known elements of flowering-time pathways through sequencing and bioinformatics analysis. These genes are highly conserved in citrus and other species, suggesting that the functions of the related proteins in controlling reproductive development may be conserved as well.</p> <p>Conclusion</p> <p>Our results provide a foundation for comparative gene expression studies between WT and precocious trifoliate orange. Additionally, a number of candidate genes required for the early flowering process of precocious trifoliate orange were identified. These results provide new insight into the molecular processes regulating flowering time in citrus.</p

'Valencia' sweet orange tree flowering evaluation under field conditions Avaliação do florescimento de laranjeiras valência em condição de campo

Since citrus flowering is a key process in citriculture and its evaluation is often difficult due to the canopy structure and field sampling, the aim of this research was to give some directions regarding the evaluation of flowering in field-grown sweet orange plants. This study was conducted in a citrus orchard of sweet orange plants cv. 'Valencia' [Citrus sinensis (L.) Osbeck] grafted on 'Cleopatra' mandarin (Citrus reshni hort. ex Tanaka) or 'Rangpur' lime (Citrus limonia Osbeck) rootstocks, with North-South orientation. Generative structures [buds, flowers and fruitlets (diameter < 3 cm)] were quantified weekly between August and November 2005, by using a 1 m² frame positioned at the middle third of plant canopy, sampling a volume of about 1 m³. Frames were divided in two parts so that two people could take measurements, and were positioned at Southeast, Southwest, Northeast and Northwest orientations, using seven plants. The following flowering parameters were: (i) number of plants necessary for a representative evaluation of flowering; (ii) plant canopy position to be sampled, and (iii) volume to be evaluated. When considering practical aspects of crop production, a rapid, simple and representative method for flowering evaluation is necessary, especially for growers that frequently have to make strategic decisions about the management of citrus groves. The flowering of field-grown 'Valencia' sweet orange plants can be rapidly assessed by considering at least five plants and sampling canopy volumes of 0.5 m³ in at least one canopy position on each side of the plant row.<br>O florescimento dos citros é um processo chave na citricultura e sua avaliação é dificultada devido à estrutura da copa e amostragem em campo. O objetivo desse artigo foi fornecer algumas indicações de como avaliar o florescimento de laranjeiras em condição de campo. Esse estudo foi conduzido em um pomar de laranjeiras 'Valência' [Citrus sinensis (L.) Osbeck] enxertadas em tangerineira 'Cleópatra' (Citrus reshni hort. ex Tanaka) ou limoeiro 'Cravo' (Citrus limonia Osbeck), com orientação Norte-Sul. As estruturas reprodutivas [botões florais, flores e frutos (diâmetro < 3 cm)] foram quantificadas semanalmente entre agosto e novembro de 2005, utilizando guias de 1 m² posicionadas no terço médio da copa das plantas, amostrando aproximadamente um volume de 1 m³. As guias foram divididas em duas partes para que duas pessoas pudessem realizar as avaliações, e posicionadas nas orientações sudeste, sudoeste, nordeste e noroeste, em sete plantas. Alguns aspectos do florescimento dos citros foram avaliados: (i) quantas plantas são necessárias para uma amostragem representativa do florescimento; (ii) em qual orientação deve ser feita a medida e (iii) qual volume da copa das plantas que deve ser amostrado. Ao se considerar os aspectos práticos da produção dos citros, um método rápido, simples e representativo é necessário para avaliar o florescimento, especialmente quando produtores têm que freqüentemente tomar decisões estratégicas no manejo dos pomares. O florescimento de laranjeiras 'Valência' em condição de campo pode ser rapidamente avaliado considerando-se pelo menos cinco plantas e amostrando-se volumes de copa de 0,5 m³ em pelo menos uma posição da copa em cada lado da linha de plantio