Browsing by Author "Ruiz, Rafael"

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    Boron dynamics related to fruit growth and seed production in kiwifruit (Actinidia deliciosa, cv. Hayward)
    (2010) Sotomayor, Carlos; Norambuena, Paulina; Ruiz, Rafael
    C. Sotomayor, P. Norambuena, and R. Ruiz. 2010. Boron dynamics related to fruit growth and seed production in kiwifruit (Actinidia deliciosa, cv. Hayward). Cien. Inv. Agr. 37(1):133-141. The effect of foliar boron treatments on fruit growth and seed development in Actinidia deliciosa, cv. Hayward, was studied. The distal leaves (BH) or flowers (BF) of a shoot were sprayed with 500 mg L-1 boric acid during the flowering period. The mobility of boron from the leaves to the flowers through the phloem was determined by spraying only the leaves. From 0 to 96 h after treatment, leaves and flowers were sampled and total boron was assessed. At harvest time, fruit weight and diameter plus seed weight and number were measured for the different treatments. The weight of fruits growing from shoots with boron-treated leaves were 14.1% higher than the control, while the weight of fruits derived from boron-treated flowers was 17% higher than that of fruits from untreated flowers. Regarding fruit length, significant differences between boron treatments and the control were observed, with an 8.2% and 8.5% increase for BH and BF treatments, respectively. No significant differences were found in fruit diameter. Fruits grown from shoots with boron-treated leaves had 43% more seeds than fruit grown from untreated control shoots, while fruits resulting from boron-treated flowers had 44% more seeds. This demonstrates the positive effect of boron treatment in seed production. No differences were observed in seed weight between treatments. The correlation coefficient between seed number and fruit weight was r(2)=0.1294 for BF, r(2)=0.1298 for BH and r(2)=0.0002 for the control. There was no variation in non-treated leaves and flowers with respect to boron concentration for a 96 h time period. On the contrary, in sprayed leaves boron levels reached up to 16 mg kg(-1) between 24 and 48 h and slightly decreased after 96 h, demonstrating the boron absorption capacity of leaves. In the flowers from the shoots with boron-treated leaves, there was a significant 14 mg kg(-1) increase in boron concentration from 24 to 96 h, showing boron mobility from leaves to flowers.
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    EFFECTS OF FOLIAR AND SOIL CALCIUM APPLICATION ON YIELD AND QUALITY OF TABLE GRAPE CV. 'THOMPSON SEEDLESS'
    (TAYLOR & FRANCIS INC, 2010) Bonomelli, Claudia; Ruiz, Rafael
    Table grape quality and firmness are key parameters for Chile's export, given distances from the main markets. As a consequence, calcium (Ca) fertilization has become a standard practice in the country, although its effects have not been fully evaluated. The objectives in this study were to investigate the effects of calcium fertilization on table grape nutrition and quality. A two-year field trial was conducted in central Chile, using grapevines (Vitis vinifera) cv. 'Thompson seedless', grown on an overhead trellis system. Calcium (CaCl2) application treatments included foliar, soil, foliar plus soil, and a control without Ca fertilization. Calcium and other nutrients concentration were determined afterwards in soil, leaves, and berries. Also, yield and some fruit quality parameters were evaluated. Calcium application method did not have an effect on soil, leaf or fruit Ca content, neither on yield and berry sugar concentration, with levels being similar to the control treatment. Additionally, in treatments where CaCl2 was applied to soil, chlorides concentration in soil, leaves, and berries were higher. Also, berries were larger, more turgent, with lower dry matter and larger cells. In the second season, in these same treatments, berry firmness at harvest was higher, but this effect disappeared after the storage simulation period. These results question the validity that Ca applications might improve table grape postharvest quality for growing conditions similar to the ones in this experiment. The temporal changes in berry quality parameters were attributed to higher Cl soil content and the associated plant osmoregulatory mechanisms.
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    Phloematic mobility of 10Boron in kiwifruit (Actinidia deliciosa) mixed shoots
    (2012) Sotomayor, Carlos; Ruiz, Rafael; Munoz, Luis
    C. Sotomayor, R. Ruiz, and L. Munoz. 2012. Phloematic mobility of (10)Boron in kiwifruit (Actinidia deliciosa) mixed shoots. Cien. Inv. Agr. 39(3): 563-567. Boron (B) is an essential micronutrient showing restricted mobility in plants, except in species that synthesize polyols. The ability of kiwifruit to mobilize B through phloem transport has not yet been confirmed, despite its ability to synthesize the polyol myo-inositol. This study examined kiwifruit plants in which boric acid enriched with the stable B-10 isotope was applied to the distal leaves of mixed shoots with flowers. At 24, 72 and 144 h, both B-10-treated and un-treated leaves and flowers from treated shoots were sampled and subsequently analyzed via mass spectrometry to determine the resulting B-11/B-10 ratios. Control leaves and flowers showed a natural ratio, varying between 3.82 and 4.05. In contrast, the ratios in treated leaves were 1.57 at 24 h,h 2.06 at 72 h (both of which are significantly different from the control) and similar to the control again after 144 h, at 3.83h. In the flowers from shoots with treated leaves, the ratios were 1.31 at 24 h, h1.48 at 72 h (both different from the control) and 3.67 at 144 h (similar to the control). These results indicate that the B solution was absorbed through the leaves and then rapidly retranslocated to B-demanding sinks, such as flowers, within the first 72 h. This finding clearly indicates that kiwifruit can transport boron through the phloem, which is essential knowledge for the correction of leaf and flower B deficiencies through foliar applications.