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AIM: To compare the visual function of low-vision patients with primary retinal pigmentosa(RP)before and after wearing amber filter.METHODS: Self-control before and after study. A total of 30 patients(60 eyes)with low vision who were diagnosed with primary RP in the ophthalmology clinic of Xi'an No.1 Hospital from August 2021 to March 2022 were collected. The uncorrected distance visual acuity(UCDVA), best-corrected distance visual acuity(BCDVA), uncorrected near visual acuity(UCNVA), best-corrected near visual acuity(BCNVA), visual field and Farnsworth-Munsell(FM)-100 color visions were recorded before and after wearing amber filter. The contrast sensitivity(CS)in three visual environments including bright room, darkroom and darkroom with glare was measured and recorded respectively, and the changes of those parameters were analyzed before and after wearing filter.RESULTS: UCDVA and BCDVA after wearing the filter were better than those before wearing(t=-2.32, P<0.001; t=-6.77, P<0.001), while there was no statistically significant difference in UCNVA and BCNVA before and after wearing filter. The visual field index(VFI)after wearing filter was lower than that before wearing(t=8.62, P<0.001), and the mean defect(MD)of visual field was greater than that before wearing(t=7.73, P<0.001). FM100 color chess test showed that both total error score(TES)and partial error score(PES)in multiple regions were higher than those before wearing filter(P<0.001). After wearing, the CS of each frequency band in the environment of bright room and darkroom with glare was higher than that before wearing(P<0.001), and there was no statistically significant difference in each frequency band before and after wearing amber filter under the environment of darkroom without glare.CONCLUSION: Patients with low vision of primary RP showed improved UCDVA and BCDVA, but unchanged UCNVA and BCNVA after wearing amber filter, while the visual field and color discrimination were worse than those before wearing filter. The CS of the bright room and darkroom with glare environment was improved than before wearing filter, while there were no significant changes in CS under darkroom without glare.
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The stem sap flow rate of Haloxylon ammodendron plantation in the Minqin oasis-desert ectone was measured by the thermal dissipation probe (TDP). A cross-correlation analysis was used to estimate the time lag between the stem sap flow and the environmental factors influencing transpiration, including photosynthetically active radiation (PAR) and water vapor pressure deficit (VPD). The results showed that the stem sap flow rate of H. ammodendron had substantial seasonal variation, with the monthly average sap flow being the highest in June and the lowest in August. There was an obvious time lag between the stem sap flow of H. ammodendron and PAR and VPD. The stem sap flow was lagged behind PAR for 80 min but it was ahead of VPD for 114 min. Additionally, the time lag exhibited significant difference among different months during the growth season from May to September. The sap flow of H. ammodendron was more dependent on the variation of PAR on the daily scale than VPD, but it was more closely related to VPD during the day time. The time lag between the stem sap flow and PAR/VPD had no significant correlation with the tree factors (including plant height, ground diameter, diameter at 50 cm height, under branch height, canopy size) and the nocturnal sap flow.
Assuntos
Chenopodiaceae/fisiologia , Caules de Planta/fisiologia , China , Clima Desértico , Transpiração Vegetal , Estações do Ano , Árvores , ÁguaRESUMO
This study continuously measured the evapotranspiration (ET) of degraded Haloxylon ammodendron shrub plantation of Minqin oasis-desert ectone using an eddy covariance system for ET, and TDR for soil moisture profile, analyzing ET in relation to the weather conditions and describing the responses of ET to the microclimate variables in different weather from July 2014 to June 2015. Results showed that the hourly ET dynamics had an apparent seasonal trend in the growing season. This trend gradually increased in the beginning of season from the low level of non-growing season, reached its maximum peak value (0.07 mm·h-1) in the most physiologically active period, and decreased to the minimum peak value (0.01 mm·h-1) in December. The diurnal change in ET of the plantation depended on the weather conditions. The ET fluctuated less with a small magnitude in a cloud day, but fluctuated obviously with a greater magnitude after rain if weather was clear. After a strong rainfall (>9 mm·d-1), ET increased sharply to a high level of 28 folds prior to rain, at which it took four clear days to gradually decease to the pre-rain ET level. The yearly ET over H. ammodendron plantation was 108 mm, equivalent to 98% of annual precipitation. Soil moisture was the water source for ET. Therefore, soil moisture was the dominant factor for theET over the plantation. Net radiation, photosynthesis active radiation, air temperature, and vapor pressure deficit were the microclimate variables to drive the transpiration of vegetation and evaporation over the soil surface, being the major factors forET over the plantation. The regression equation of ET to the dominant factor and major factors had a coefficient of multiple determination (R2) over 0.80.
