Relation of carbohydrate reserves with the forthcoming crop, flower formation and photosynthetic rate, in the alternate bearing Salustiana sweet orange (Citrus sinensis L.)

[EN] The aim of this work was to assess the relation between carbohydrate levels and flower and fruit production, as well as the role of carbohydrates on CO(2) fixation activity, by analysis of leaves, twigs and roots from the alternate bearing 'Salustiana' cultivar of sweet orange (Citrus sinensis [L.] Osbeck). A heavy crop load (on year) did not affect photosynthesis activity when compared to non-fruiting trees (off year). Fruiting trees accumulated most of the fixed carbon in mature fruits, whilst no accumulation was observed in roots before harvest. Non-fruiting trees transported part of the fixed carbon to the roots and mobilize it for growth processes and, at the end of the season (December), store it as reserves. Reserve carbohydrates accumulation in leaves started by early December for both tree types, showing the same levels in on and off trees until spring bud sprouting. A heavy flowering after an off year caused the rapid mobilization of the stored reserves, which were exhausted at full bloom. We found no evidence on carbon fixation regulation by either fruit demand or carbohydrate levels in leaves. Carbohydrate reserves played little or no role over fruit set, which actually relied on current photosynthesisWe thank Ing. Agr. J.M. Torres (ANECOOP, Valencia, Spain) for providing the orchard facilities and logistic help, the R + D + i Linguistic Assistance Office at the Universidad Politecnica de Valencia for their help in revising this article and Y. Bordon for her cooperation in some experiments. Thanks are due also to Dr. Olivares for the critical review of the manuscript. This research was funded by grants from the Conselleria de Agricultura, Pesca y Alimentacion (GV-CAPA00-11) and the Conselleria diEmpresa, Universitat i Ciencia, Generalitat Valenciana (Grupos 04/059).Monerri Huguet, MC.; Fortunato De Almeida, A.; Molina Romero, RV.; González Nebauer, S.; García Luís, MD.; Guardiola Barcena, JL. (2011). Relation of carbohydrate reserves with the forthcoming crop, flower formation and photosynthetic rate, in the alternate bearing Salustiana sweet orange (Citrus sinensis L.). Scientia Horticulturae. 129(1):71-78. https://doi.org/10.1016/j.scienta.2011.03.009S7178129

Self-organized criticality in deterministic systems with disorder

Using the Bak-Sneppen model of biological evolution as our paradigm, we investigate in which cases noise can be substituted with a deterministic signal without destroying Self-Organized Criticality (SOC). If the deterministic signal is chaotic the universality class is preserved; some non-universal features, such as the threshold, depend on the time correlation of the signal. We also show that, if the signal introduced is periodic, SOC is preserved but in a different universality class, as long as the spectrum of frequencies is broad enough.Comment: RevTex, 8 pages, 8 figure

Fenologia e produção de cultivares de amoreira-preta em sistema agroecológico.

A amoreira-preta é uma espécie de exploração recente no Brasil. Nos últimos ano, s tem sido dada especial atenção ao cultivo orgânico ou agroecológico dessa espécie. O objetivo deste trabalho foi verificar o comportamento fenológico e produtivo das cultivares de amora-preta ‘Tupy’, ‘Guarani’, ‘Caingangue’, ‘Cherokee’ e ‘Brazos’, e das seleções denominadas ‘seleção 97’ e ‘seleção 787’ na região de Pelotas, Rio Grande do Sul(RS), em sistema agroecológico. O trabalho foi realizado na Estação Experimental de Cascata (EEC), Embrapa Clima Temperado. As plantas foram dispostas no pomar, em blocos varietais aleatórios, com 10 plantas por genótipo, perfazendo quatro linhas com duas cultivares por linha. Foram observadas as datas de início da floração e fim da floração, início e final de colheita, massa (gramas) e número de frutos por planta, teor de sólidos solúveis totais (ºBrix), produção média por planta (g pl-1) e produtividade estimada por hectare (kg ha-1). Para análise das características dos frutos, a média de cada ano de avaliação (três) foi considerada como uma repetição. Na região de Pelotas-RS, é viável o cultivo agroecológico de amoreira-preta. Não há diferenças de produção, produtividade, número de frutos e teores de sólidos solúveis totais entre os genótipos estudados

Porcine follicular fluid concentration of free insulin-like growth factor-I collected from different diameter ovarian follicles

The study aimed to quantify the concentrations of free IGF-I in serum and fluid of ovarian follicles in pre-pubertal gilts and describe the ovarian morphology by measuring the size of the ovaries and counting the number of surface follicles. Ovaries (n=1,000) from pre-pubertal gilts were obtained immediately after slaughter. A total of 10 samplings were performed, with ovaries obtained from 50 females for each collection. The follicles situated on the surface of each ovary were classified as small (SFs, 2 to 5mm in diameter) or large (LFs 6 to 10mm in diameter) and the follicular fluid was obtained by follicle aspiration. The collection of serum samples was performed after the gilts exsanguination using sterile tubes. From the pool of serum and follicular fluid obtained from 50 females, the concentration of free IGF-I was determined in each sample using an enzyme immunoassay kit (ELISA). The description of ovarian morphometry was performed in 100 ovaries from randomly selected gilts. The larger and smaller lengths of ovaries were measured, and the total number of SFs and LFs present on the surface of each ovary were also counted. The IGF-I concentration was greater (P<0.05) in LFs (170.92±88.29 ng/mL) compared with SFs (67.39±49.90ng/mL) and serum (73.48±34.63ng/mL). The largest and smallest length of the ovaries was 26.0±3.0 and 19.0mm ±2.0mm, respectively. The number of SFs (70.86±25.76) was greater (P<0.01) than LFs (6.54±5.26). The study concluded that LFs present greater levels of IGF-I when compared with SFs and blood, which is related to increased activity of the LFs and its differentiation to ovulation. In addition, ovaries of pre-pubertal gilts have a higher number of SFs compared to LFs. Therefore, our study demonstrated unique data regarding the physiological concentration of free IGF-I in ovarian follicles, that can be used in future research to evaluate the addition of this hormone in the in vitro production media of porcine embryos with the goal to improve the technique efficiency