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The effect of water deficit on chlorophyll fluorescence, sugar content, and growth parameters of strawberry (Fragaria×ananassa Duch. cv. Elsanta) was studied. Drought stress caused significant reductions in leaf water potential, fresh and dry masses,
leaf area, and leaf number. A gradual reduction of photochemical quenching (qP) and quantum efficiency (ΦPS2) was observed under drought stress while non-photochemical quenching (qN) increased. Maximum efficiency of photosystem 2 (Fv/Fm) was not affected by drought stress. 相似文献
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Roberto L. Salomón Kathy Steppe Jean M. Ourcival Selwyn Villers Jesús Rodríguez-Calcerrada Roderick Schapman Jean M. Limousin 《Plant, cell & environment》2020,43(6):1528-1544
Stem water storage capacity and hydraulic capacitance (CS) play a crucial role in tree survival under drought-stress. To investigate whether CS adjusts to increasing water deficit, variation in stem water content (StWC) was monitored in vivo for 2 years and related to periodical measurements of tree water potential in Mediterranean Quercus ilex trees subjected either to permanent throughfall exclusion (TE) or to control conditions. Seasonal reductions in StWC were larger in TE trees relative to control ones, resulting in greater seasonal CS (154 and 80 kg m−3 MPa−1, respectively), but only during the first phase of the desorption curve, when predawn water potential was above −1.1 MPa. Below this point, CS decreased substantially and did not differ between treatments (<20 kg m−3 MPa−1). The allometric relationship between tree diameter and sapwood area, measured via electrical resistivity tomography, was not affected by TE. Our results suggest that (a) CS response to water deficit in the drought-tolerant Q. ilex might be more important to optimize carbon gain during well-hydrated periods than to prevent drought-induced embolism formation during severe drought stress, and (b) enhanced CS during early summer does not result from proportional increases in sapwood volume, but mostly from increased elastic water. 相似文献
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This investigation assessed the effects of termite mound material (TMM) on the physical properties of sandy soil and on tomato (Solanum lycopersicum L.) growth characteristics and water use efficiency. TMM combined with organic manure, TMM combined with rice straw mulching and organic manure, organic manure alone (OM) and unamended (T0) were the treatments used. Results showed that soil treated with TMM had more clay sized particles and organic carbon content than T0 and OM. In TMM-treated soil, more water was being retained at both field capacity and permanent wilting point. The application of TMM did not affect the amount of plant available water. Saturated hydraulic conductivity also remained unaffected by the TMM application, but increased with the organic matter treatment. Tomatoes grown in TMM amended soils had greater plant height and more leaves, fruit and biomass. No specific rate of TMM application was better for all parameters being assessed. The amount of water used by the tomatoes was significantly correlated (P?<?0.01) with fresh fruit yield (r?=?0.82), leaf area index (r?=?0.82) and total dry matter production (r?=?0.68). While TMM did not specifically affect plant water-use efficiency, this parameter was generally improved in amended soils. 相似文献
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Katrijn Van Laere Soraya C. França Hein Vansteenkiste Johan Van Huylenbroeck Kathy Steppe Marie-Christine Van Labeke 《Acta Physiologiae Plantarum》2011,33(4):1149-1156
In this study, we analysed morphological, anatomical and physiological effects of polyploidisation in Spathiphyllum
wallisii in order to evaluate possible interesting advantages of polyploids for ornamental breeding. Stomatal density was negatively
correlated with increased ploidy level. Stomatal size increased in polyploids. Tetraploid Spathiphyllum plants had more ovate and thicker leaves. The inflorescence of tetraploids had a more ovate and thicker spathum, a more cylindrical
spadix and a thicker but shorter flower stalk. Biomass production of the tetraploids was reduced, as expressed by lower total
dry weights, and tetraploids produced fewer shoots and leaves compared with their diploid progenitors. Furthermore, tetraploid
Spathiphyllum plants were more resistant to drought stress compared with diploid plants. After 15 days of drought stress, diploids showed
symptoms of wilting, while the tetraploids showed almost no symptoms. Further, measurements of stomatal resistance, leaf water
potential, relative water content and proline content indicated that the tetraploid genotypes were more resistant to drought
stress compared with the diploids. 相似文献
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Background and aims
Irrigation strategies for glasshouse tomato are often based on solar radiation sums. However, due to new energy-saving climate control, current strategies might result in inappropriate irrigation. Because of the limited water buffering capacity of soilless growing media like rockwool, this could have adverse effects on fruit production and quality. We present an overview of tomato plant ecophysiological responses to substrate water availability to allow the evaluation of mechanistic hypotheses about internal plant water storage and depletion and reversible stem-fruit water transport.Methods
The hydraulic properties of the growing medium were determined and plant water uptake, stem and fruit diameter variations were studied.Results
A low substrate matric suction (?2 to ?3?kPa) had a significant effect on stem and fruit growth dynamics. The substrate water retention curve indicated a sharp decrease in hydraulic conductivity, limiting the water availability for plant roots significantly.Conclusions
The hydraulic properties of the growing medium are of utmost importance for plant water uptake, and should therefore be incorporated in plant models describing water flow. Internally stored water responds instantaneously to varying water availability and rates of water backflow from tomato fruits can be quite substantial. 相似文献19.
BACKGROUND AND AIMS: Stomatal oscillations have been reported in many plant species, but they are usually induced by sudden step changes in the environment when plants are grown under constant conditions. This study shows that in navel orange trees (Citrus sinensis) pronounced stomatal oscillations occur and persist under natural climatic conditions. METHODS: Oscillations in stomatal conductance were measured, and related to simultaneous measurements of leaf water potential, and flow rate of sap in the stems of young, potted plants. Cycling was also observed in soil-grown, mature orchard trees, as indicated by sap flow in stem and branches. KEY RESULTS: Oscillations in stomatal conductance were caused by the rapid propagation and synchronization of changes in xylem water potential throughout the tree, without rapid changes in atmospheric conditions. CONCLUSIONS: The results show marked stomatal oscillations persisting under natural climatic conditions and underscore the need to discover why this phenomenon is so pronounced in orange trees. 相似文献
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