CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Embora se tenha muitos estudos sobre estresse salino, pouco se conhece sobre os mecanismos individuais de sÃdio (Na+) e cloro (Cl-) na fisiologia de plantas expostas à salinidade. Baseado nisso, objetivou-se, atravÃs deste estudo, avaliar a extensÃo com que os Ãons Na+ e Cl- sÃo acumulados em diferentes partes jovens de feijÃo-caupi [Vigna unguiculata (L.) Walp.] e as suas possÃveis interferÃncias sobre as medidas de transpiraÃÃo. Para comprovar a hipÃtese que os Ãons Na+ e Cl- apresentam modelos diferentes de distribuiÃÃo nas partes vegetativas de feijÃo-caupi e que esse processo nÃo à afetado pela temperatura, foi organizada uma seqÃÃncia metodolÃgica envolvendo trÃs experimentos, onde o experimento I consistiu em avaliar a distribuiÃÃo de Na+ e Cl- em partes jovens de feijÃo-caupi submetido a concentraÃÃes crescentes de NaCl (0; 25; 50; 75 e 100 mM) durante 3 dias, onde ocorreu um maior acÃmulo de cloreto em todas as partes estudadas com exceÃÃo do caule que teve acÃmulo similar de ambos os Ãons. Baseado nessa distribuiÃÃo, utilizou-se a concentraÃÃo de 50mM, pois essa concentraÃÃo nÃo superaria a capacidade de armazenamento e, assim, seria possÃvel, nesse nÃvel, uma recuperaÃÃo (foi mantida durante 6 dias em NaCl e, a partir do 4 dia, as amostras foram divididas em dois lotes). Um lote permanecia com NaCl e o outro trocava a soluÃÃo sem NaCl e assim verificar se essa estratÃgia a planta seria capaz de recuperase. Os resultados corroboram com os obtidos no experimento I com exceÃÃo da primeira folha trifoliolada que acumulou mais Na que Cl. A literatura relata, abundantemente, que nas Ãpocas de verÃo (perÃodo do experimento I), principalmente no semi-Ãrido, as plantas acumulam mais Ãons, onde a temperatura à uma medida de fator climÃtico que pode interferir na distribuiÃÃo de Ãons e esse efeito està ligado à transpiraÃÃo. No experimento III, foi avaliado o efeito combinado de estresse salino e de temperaturas elevadas, com concentraÃÃes de 0 e 100 mM de NaCl e exposiÃÃo a temperaturas de 27; 32; 37 e 42ÂC, separadamente, por um fotoperÃodo de 12 horas. Os resultados corroboram com os obtidos, anteriormente, em que o sÃdio concentrou-se mais nas raÃzes e caules das plantas quando tratadas nas duas Ãltimas temperaturas. Em relaÃÃo ao Ãon cloreto, foi verificado um comportamento similar aos experimentos anteriores, pois este se acumulou, em maior proporÃÃo, nas folhas sob temperaturas de 32 a 42ÂC. Notadamente, o acÃmulo de cloreto està associado à quantidade de Ãgua absorvida durante a aplicaÃÃo do estresse. Em relaÃÃo à transpiraÃÃo, os resultados tambÃm corroboram com os anteriores. Dessa forma, conclui-se que, independente da concentraÃÃo, tempo, recuperaÃÃo e temperatura, o sÃdio à mais concentrado na raiz e caule, enquanto o cloreto concentra-se nas folhas. / Although it has many studies on salinity, little is known about the mechanisms of individual Na+ and Cl- in the physiology of plants exposed to salinity. Based on that meant to use this study to evaluate the extent to which the ions Na+ and Cl- are accumulated in different parts of young cowpea [Vigna unguiculata (L.) Walp.] and the possible interference on the steps of perspiration. To prove the hypothesis that the ions present different models of distribution in vegetative parts of cowpea and this process is not affected by temperature. It organized a string surrounding methodological three experiments. Where will I study was to evaluate the distribution of Na+ and Cl- young in parts of cowpea subjected to increasing concentrations of sodium chloride (0, 25, 50, 75 and 100 mM) for 3 days. In what was a greater accumulation of sodium chloride that in all parts studied, except the stem which accumulation in the equivalent proportions. Based on this distribution used with a concentration of 50 mM because it would not exceed the storage capacity and it was possible that a recovery level (it was held for 6 days in NaCl and from the 4th day the samples were divided into two lots. A lot remains NaCl and other exchanges with the solution without NaCl and thus verify that this strategy the plant would be able to recover it. The results corroborated with those obtained in the experiment I except the 1st trifoliate leaves that accumulated more in that Cl. The literature reports that plenty of times in the summer (period of the experiment I), particularly in semi-arid plants accumulate more ions. Where the temperature is a measure of climatic factors that may interfere with the distribution of ions and whether this effect is linked to transpiration. And then we performed the experiment III to assess the combined effect of salinity and high temperatures, in concentrations from 0 to 100 mM NaCl. Exposed to temperatures of 27, 32, 37 and 42 C, separately, during a photoperiod of 12 hours. The results corroborate with those obtained previously in the sodium has focused more on the roots and stems when treated in the last two temperatures. Regarding the chloride ion, was found a behavior similar to previous experiments, as they accumulated in greater proportion in the leaves at temperatures of 32 to 42 C. Notably the accumulation of chloride, is associated withthe amount of water absorbed during the implementation of stress. Regarding transpiration also corroborate the previous results. Thus it appears that regardless of concentration, time, temperature recovery and the ash is more concentrated in the root and stem while chloride is concentrated in the leaves.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / To evaluate the responses of canarana grass erecta lisa (Echinochloa pyramidalis Lam.) grazed by dairy heifers, this study was conduct. Was used a factorial arrangement 2.0 x 2.0 (two frequencies and two defoliation intensity) in completely plots randomized design with five replicates (paddocks). The defoliation frequencies corresponded to interception from 85 and 95% of active photosynthetic radiation and the defoliation intensity corresponded the residual leaf area index 1.0 and 2.0. Were evaluated the growth in regrowth by morphogenesis method, the gas exchange and biomass flow. Were analyzed the growth characteristic: crop growth rate (CGR), relative growth rate (RGR), net assimilate rate (NAR), leaf area ratio (LAR), specific leaf area (SLA), and leaf weight ratio (LWR), also were evaluates: total dry mass forage (TDMF), fresh dry mass forage (FDMF), fresh dry mass leaf (FDML), fresh dry mass stem (FDMS), leaf/stem ratio (L/S). The exchange gas trial were made following measurements: transpiration (E), stomatal conductance (gs), photosynthesis (A), internal CO2/reference CO2 ratio (Ci/CR), efficient use of water (EUW), intrinsic use of water (IUW) and relative index of the chlorophyll (RIC). The variable belonging to biomass flow were: leaf elongation rate (LER), and stem (SER), the elongation rate of the leaf 1/ elongation rate of the leaf 2 (ERL1/ERL2), leaf previous senescence rate (LPVSR), leaf posterior senescence rate (LPOSR) and leaf total senescence rate (LTSR), leafs live number (LLN) and total leafs number (TLN), life leaf time (LLT), leaf appearance rate (LAR) and crop accumulation rate (CAR). The TDMF, FDMF, FDMS and FDML presented increasing values based on age, The L/S ratio showed x. Were obtained increasing values to CGR, and decreasing values RGR, NAR. The values of SFA were increased to 20 days, after showed decreasing values. On the exchange gas trial, there wasnât difference between management strategies (P>0.05), however on post-grazing the variables EUW and IUW showed lower average (P<0.05), to 85% IAPR. About to cycles of the grazing the evaluates of pre-grazing, the E was lower to 95% IAPR management x intensity 2.0 (P<0.05) The EUW showed lower values to 95% IAPR x intensity 1and higher to 95% x intensity 2 (P<0.05). Evaluates made on post-grazing there was difference to the content of the chlorophyll that showed lower average to intensity 1.0 (P<0.05). On the biomass flow trial, the PVSR, LLN and ALR presented lower values to the less defoliation frequencies (P<0.05), the LPOSR showed lower values to defoliation frequencies. The physiologic characteristic were changed by differences defoliation frequencies and intensity. The growth index of canopy RGR, NAR were committed with the age, but the same not occur to the CGR. The canarana grass should be handled frequently defoliation of 95% interception of photosynthetically active radiation associated whit a residual leaf index 2.0. / Objetivou-se avaliar as respostas do capim-canarana erecta lisa (Echinochloa pyramidalis Lam.) ao pastejo por novilhas leiteiras num arranjo fatorial 2,0 x 2,0 (duas frequÃncias e duas intensidades de desfolhaÃÃo) num delineamento em blocos completos casualizados com cinco repetiÃÃes (piquetes). As frequÃncias de desfolhaÃÃo corresponderam à intercepÃÃo de 85 e 95% da radiaÃÃo fotossinteticamente ativa e as intensidades de desfolhaÃÃo corresponderam aos Ãndices de Ãrea foliar residual de 1,0 e 2,0. Foram avaliados: o crescimento em rebrotaÃÃo pelo mÃtodo da morfogÃnese, as trocas gasosas e o fluxo de biomassa. Das caracterÃsticas de crescimento foram analisadas: a taxa de crescimento da cultura (TCC), a taxa de crescimento relativo (TCR), a taxa de assimilaÃÃo lÃquida (TAL), a razÃo de Ãrea foliar (RAF), a Ãrea foliar especÃfica (AFE) e a razÃo de peso foliar (RPF). TambÃm foram avaliadas: a massa seca de forragem total (MSFT), a massa seca de forragem verde (MSFV), a massa seca de lÃminas foliares verdes (MSLV), a massa seca de colmos verdes (MSCV), a relaÃÃo folha/colmo (F/C). Para o ensaio de trocas gasosas, foram feitas mediÃÃes das seguintes variÃveis: transpiraÃÃo (E), condutÃncia estomÃtica (gs), fotossÃntese (A), relaÃÃo CO2 interno/CO2 de referÃncia (Ci/CR), uso eficiente da Ãgua (UEA), uso intrÃnseco da Ãgua (UIA) e Ãndice relativo de clorofila (IRC). As caracterÃsticas do fluxo de biomassa incluÃram: as taxas de alongamento foliar (TAlF) e das hastes (TAlH), a razÃo entre a taxa de alongamento da folha 1 e da folha 2 (TAlF1/TAlF2), a taxa de senescÃncia foliar anterior (TSFA), a taxa de senescÃncia posterior (TSFP) e a taxa de senescÃncia foliar total (TSFT), o nÃmero de folhas vivas (NFV), o nÃmero de folhas totais (NFT); o tempo de vida da folha (TVF); a taxa de aparecimento da folha (TApF) e a taxa de acÃmulo da cultura (TAC). A MSFT, MSFV, MSCV e MSLV apresentaram valores crescentes em funÃÃo da idade, a relaÃÃo F/C apresentou valores decrescentes. Obtiveram-se valores crescentes para TCC, para TCR, TAL os valores foram decrescentes. Os valores de AFE foram crescentes atà aos 20 dias, seguido de valores decrescentes. No ensaio de trocas gasosas, prÃ-pastejo, nÃo houve diferenÃa para as estratÃgias de manejo (P>0,05). Entretanto, no pÃs-pastejo as variÃveis UEA, A e UIA apresentaram mÃdias menores (P<0,05), para 85% IRFA. Com relaÃÃo aos ciclos de pastejo para leituras de prÃ, a E foi menor para o manejo 95% IRFA x intensidade 2 (P<0,05). A UEA apresentou valores inferiores em 95% IRFA x intensidade 1 e superiores para 95% IRFA x intensidade 2 (P<0,05). Para leitura no pÃs-pastejo, houve diferenÃa para o conteÃdo de clorofila, que apresentou valores inferiores para intensidade 1,0 (P<0,05). No ensaio de fluxo de biomassa A TSFA, NFV e TApF apresentaram valores menores para as menores frequÃncias de desfolhaÃÃo (P<0,05), a TSFP apresentou menores valores para maiores frequÃncias de desfolhaÃÃo. As caracterÃsticas fisiolÃgicas foram alteradas pelas diferentes frequÃncias e intensidade de desfolhaÃÃo. Os Ãndices de crescimento do dossel TCR, TAL foram comprometidos com o aumento da idade, mas o mesmo nÃo ocorreu para o e TCC. O capim-canarana deve ser manejado com frequÃncia de desfolhaÃÃo de 95% de interceptaÃÃo da radiaÃÃo fotossinteticamente ativa associada a um Ãndice de Ãrea foliar residual de 2,0.