• Temporal variation in sap-flow-scaled transpiration and cooling effect of a subtropical Schima superba plantation in the urban area of Guangzhou

    分类: 生物学 >> 植物学 提交时间: 2018-01-22

    摘要: Thermal dissipation probes were used to measure xylem sap flux density for a Schima superba plantation growing in the urban area of Guangzhou city, South China. Stand transpiration was calculated by multiplying mean sap flux density by total sapwood area. The peak of sap flux density occurred later in wet season than in dry season. The maximum of daily sap flux density was the highest of 59 g m-2 s-1 in July and August, and the lowest of 28 g m-2 s-1 in December. During November 2007- October 2008 and during November 2008-October 2009, the stand transpiration was 263.2 and 291.6 mm, respectively. In the study periods, stand transpiration in wet season (from April to September) could account for about 58.5% and 53.8% of the annual transpiration, respectively. Heat energy absorbed by tree transpiration averaged 1.4×108 and 1.6×108 kJ per month in the Schima superba plantation with the area of 2885 m2, and temperature could be reduced by 4.3 and 4.7 oC s-1 for 10 m3 air.

  • The tomato mutant ars1 (altered response to salt stress 1) identifies an R1‐type MYB transcription factor involved in stomatal closure under salt acclimation

    分类: 生物学 >> 植物学 >> 植物生理学 提交时间: 2016-05-04

    摘要: A screening under salt stress conditions of a T-DNA mutant collection of tomato (Solanum lycopersicum L.) led to the identification of the altered response to salt stress 1 (ars1) mutant, which showed a salt-sensitive phenotype. Genetic analysis of the ars1 mutation revealed that a single T-DNA insertion in the ARS1 gene was responsible of the mutant phenotype. ARS1 coded for an R1-MYB type tran ARS1 did not affect this agronomic trait. The stomatal behaviour of ars1 mutant leaves induced higher Na+ accumulation via the transpiration stream, as the decreases of stomatal conductance and transpiration rate induced by salt stress were markedly lower in the mutant plants. Moreover, the mutation affected stomatal closure in a response mediated by abscisic acid (ABA). The characterization of tomato transgenic lines silencing and overexpressing ARS1 corroborates the role of the gene in regulating the water loss via transpiration under salinity. Together, our results show that ARS1 tomato gene contributes to reduce transpirational water loss under salt stress. Finally, this gene could be interesting for tomato molecular breeding, because its manipulation could lead to improved stress tolerance without yield penalty under optimal culture conditions.

  • Estimation of evapotranspiration from artificial forest in mountainous areas of western Loess Plateau based on HYDRUS-1D model

    分类: 地球科学 >> 大气科学 提交时间: 2024-12-17 合作期刊: 《干旱区科学》

    摘要: Evapotranspiration is the most important expenditure item in the water balance of terrestrial ecosystems, and accurate evapotranspiration modeling is of great significance for hydrological, ecological, agricultural, and water resource management. Artificial forests are an important means of vegetation restoration in the western Loess Plateau, and accurate estimates of their evapotranspiration are essential to the management and development of water use strategies for artificial forests. This study estimated the soil moisture and evapotranspiration based on the HYDRUS-1D model for the artificial Platycladus orientalis (L.) Franco forest in western mountains of Loess Plateau, China from 20 April to 31 October, 2023. Moreover, the influence factors were identified by combining the correlation coefficient method and the principal component analysis (PCA) method. The results showed that HYDRUS-1D model had strong applicability in portraying hydrological processes in this area and revealed soil water surplus from 20 April to 31 October, 2023. The soil water accumulation was 49.64 mm; the potential evapotranspiration (ETp) was 809.67 mm, which was divided into potential evaporation (Ep; 95.07 mm) and potential transpiration (Tp; 714.60 mm); and the actual evapotranspiration (ETa) was 580.27 mm, which was divided into actual evaporation (Ea; 68.27 mm) and actual transpiration (Ta; 512.00 mm). From April to October 2023, the ETp, Ep, Tp, ETa, Ea, and Ta first increased and then decreased on both monthly and daily scales, exhibiting a single-peak type trend. The average ratio of Ta/ETa was 0.88, signifying that evapotranspiration mainly stemmed from transpiration in this area. The ratio of ETa/ETp was 0.72, indicating that this artificial forest suffered from obvious drought stress. The ETp was significantly positively correlated with ETa, and the R2 values on the monthly and daily scales were 0.9696 and 0.9635 (P<0.05), respectively. Furthermore, ETa was significantly positively correlated with temperature, solar radiation, and wind speed, and negatively correlated with relative humidity and precipitation (P<0.05); and temperature exhibited the highest correlation with ETa. Thus, ETp and temperature were the decisive contributors to ETa in this area. The findings provide an effective method for simulating regional evapotranspiration and theoretical reference for water management of artificial forests, and deepen understanding of effects of each influence factors on ETa in arid areas.