Rela es entre o potencial e a temperatura da folha de plantas de milho e sorgo submetidas a estresse h赤drico = Relations between the potential and temperature of the corn and sorghum leafs submitted water stress

作者：Pedro Abel Vieira Junior; Durval Dourado Neto; Ricardo Ferraz de Oliveira; Lazaro Eustaquio Pereira Peres

来源：Acta Scientiarum - Agronomy, 2007.

• agua
• anisohidrico
• isohidrico
• Zea mays L.
• Sorghum bicolor L
• water
• anizohydric
• hizohydric
• Zea mays L.
• Sorghum bicolor L

Para avaliar o comportamento di芍rio do potencial h赤drico em plantas de milho e de sorgo submetidas a estresse h赤drico, relacionando com as temperaturas foliar e ambiente, foram cultivadas, em vasos individuais em estufa, cinco plantas de cada esp谷cie. At谷 o est芍dio fenol車gico de quatro folhas, o solo nos vasos foi mantido em capacidade de campo. Entre esse est芍dio e at谷 pr車ximo ao ponto de murcha a irriga o foi suspensa e foram monitoradas diariamente atemperatura ambiente (Tam), o potencial h赤drico da folha (朵folha) e a temperatura sobre a lamina foliar (Tfoext). Nas plantas que apresentavam enrolamento das folhas, foram registradas astemperaturas (Tfoint) da face interna do limbo enrolado. Tamb谷m foram calculadas as m谷dias hor芍rias dos 朵 folha para ambas as esp谷cies relacionando-os com a Tfoext, a Tfoint e as diferen as entreessas temperaturas. Ambas as esp谷cies apresentaram comportamentos semelhantes quanto ao 朵 folha e entre 13 e 15 horas verificou-se o menor 朵 folha. Apesar da significativa rela o inversa entrea Tfoext e o seu 朵 folha, em milho essa rela o n o apresenta acur芍cia para emprego da Tfoext no monitoramento do status h赤drico da planta e a Tfoint 谷 inferior 角 Tfoext, tornando-se um mecanismoque permite 角 planta a manuten o de seu metabolismo. To evaluate the daily behavior of the water potential in corn and of sorghum plants submitted to water stress, relating with the leaf and ambient temperature, were cultivated, in individual pots in greenhouse, five plants of each species. The plants were kept at field capacity until they reached the stage of four leaves. Between that stadium and close to the wilting point the irrigation was suspended and were monitored daily the ambient temperature (Tam), the water potential in the leaf (朵 folha) and the temperature on the leaf sheet (Tfoext). The plants whose leaves rolled up had their internal temperature measured (Tfoint). The average time of 朵 folha was calculated for both species relating them with Tfoex, Tfoint and thedifferences among those temperatures. Both species presented behaviors similar to 朵 folha and between 1pm to 3pm they showed the lowest 朵 folha. Despite the significant inverse relationshipbetween Tfoext and 朵 folha, in corn, this relationship does not present enough precision to use the measure os Tfoex in the control of the water status of the plant and the Tfoint was inferior to theTfoex, becoming a protection mechanism which allows the plant to maintain its metabolism.