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A B S T R A C TShading highbush blueberry plants generally leads to a delayed fruit development. Experiments have been performed to study the effects of light on fruit growth independently from the rest of the canopy. Clusters were shaded during different fruit growth periods. The equatorial diameter of the fruits as a function of days after full bloom followed a double-sigmoidal growth pattern, being fitted using a Gompertz II nonlinear mixed model, and absolute growth rates were obtained from each fitted model. Both whole-cycle shaded and second-stage shaded fruits showed a delayed peak in absolute growth curves with respect to both first-stage shaded and whole-cycle unshaded controls. Our results suggest that deficiency of light during the last stage of highbush blueberry fruits may lead to a substantial delay (of about 10-16 days) in harvest as compared with well-illuminated fruits.In order to estimate the contribution of intrinsic fruit photosynthesis to its own growth at different stages, clusters were subjected to girdling on their peduncles at different times. Girdling just before the second-stage resulted in fruits gaining between 35 and 40% of dry weight in comparison with the controls. This suggests that fruit photosynthesis may play a relevant role in fruit growth during the second sigmoidal stage, which in turn may contribute to explain the delayed growth observed in shaded fruits.

-Dep. de Agricu ltu ra e Horticultura -ESALQ -Piracicaba.Parte da dissertação de mestrado do prime iro autor para obtenção do título de MESTRE Re ce bid o pa ra pu bli caçã o em 5 de no ve mbro de 1977. 25 RESUMOA prese nte pesq ui sa fo i cond uz id a atravé s de dois ensaios com os herbicidas trifluralin, nitra lin e EPTC em duas doses cada, procurandose verificar o controle das plantas daninhas, observar os possíveis efeitos fitotóxicos à cultura após reaplicação no mesmo ano agrícola e determinar os possíveis resíduos no solo, no início do ano agrícola seguinte, que pudessem afe tar culturas rensiveis.A de te rm in aç ão do s po ss ív eis re si du os no solo, foi realizad a através de bioensa ios de rad í -culas e caulículos, utilizando-se o sorgo (Sorghum bico lor (L.) Moench .) como plan ta teste. Houv e um bom controle das plantas daninhas pelos herbicid as utilizados. A tiririca (Cyperus rotundu s L.) só fo i co ntro la da pe lo EP TC . O pi cã o -pr eto (Bid ens pilo sa L.) e a gu an xuma (Sid a spp.) não foram controlados. Nenhum dos herbicidas apre sentou fitotoxicidade à planta de feijão, mesmo após reap licação no mesmo ano ag ríco la , e não foram constatados resíduos no ano agrícola seguinte no solo, após a reaplicação no ano agrí. cola anterior.UNITERMOS: Herbicidas, Feijão, Pe rsistência. SUMMARYHER BICI DES IN BEA NS (P ha se olu s vulg aris L.): CONTROL, FITOTOXICITY AND PER -SISTANCE IN SOIL.The present research was conducted in two assays , with the herbicides triflu rali n, nitralin and EPTC in two dosi, to verify the weed control, to obse rve the possible phytotoxicity ef fects on the cr op af te r re -appl ic at ion in the same ag ricultural year, and to determine the possible resi. dues in th e soil , in th e begi nni ng of the ne xt agr ic ul tu ra l ye ar, th at mi gh t aff ect su ce pt ib le subsequent crops.The dete rmination of possible residues in the soil was made by root and shoot bioassays using th e so rg hu m (S org hu m bic olo r (L . ) Moe nc h. ) as test plant. There was a good control of weeds by th e he rb ic id es. Th e pu rp le nu tsedg e (C yp eru s ro tu nd us L.) wa s co ntro ll ed on ly by EPTC . Sp an is h ne edles (B id ens pil osa L. ) and bro om weed (Sida spp) we re not contro lled by the he rbi cide s. No ne of he rbicides presented phytoto. xic it y eff ects to th e bean cro ps even aft er re . applications in the same agricultural year, and res idues were not found in the next agricultu ral year, after re-application in the prior year.KEYWORD: Herbicides, Bean, Persistence. INTRODUÇÃOO fe ij ão (P ha se ol us vu lg ar is L. ) oc up a lugar de destaque entre os produto s agrícolas do Br as il , co nsti tu in do -se na pr in ci pa l fo nt e de pr ot ei na s pa ra gr an de pa rt e da po pu la çã o do pa ís . To da vi a é ai nd a um a cu lt ur a re le gada a se gu nd o pl an o. ap re se nt an do um ba ix o índ ice de produti vid ade . Som ent e nos últ imo s anos devido a dificuldade de abastecimento do me rc ad o in ter no , é qu e ve m se nd o da do alguma ate...

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