estimates of plant and soil water content are critical for maximizing irrigation efficiency in turfgrass management. However, laboratory assessment of leaf relative water content is a time-consuming process, especially when a large number of samples are
Air temperature and photosynthetically active radiation (PAR) effects on relative water content (RWC), rooting percentage, root count, and root mass of unmisted, subirrigated stem cuttings of two taxa were determined. Leaf RWC of `Charm' chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] decreased until roots initiated and then increased, was lower for cuttings at 23 °C photoperiod/14 °C dark than for cuttings at 31 °C photoperiod/22 °C dark, and was lower at 193 than at 69 μmol·m–2·s–1 PAR. Neither temperature nor PAR affected leaf RWC of `Dollar Princess' fuchsia (Fuchsia ×hybrida Hort. ex Vilm.), which increased linearly before and after root initiation. Rooting percentage and root count were higher with photoperiods at 31 °C than at 23 °C for chrysanthemum after 7 days and for fuchsia after 10 days. Although all cuttings of both taxa had rooted after 14 days, root dry mass was higher with photoperiods at 31 °C than at 23 °C regardless of PAR for fuchsia and at 69 μmol·m–2·s–1 PAR for chrysanthemum. Propagators wishing to use subirrigation instead of mist, fog, or enclosure can minimize the decline in leaf RWC before root initiation and increase the number and dry mass of roots of chrysanthemum by using 69 μmol·m–2·s–1 PAR and a 31 °C photoperiod/22 °C dark cycle. Root dry mass of fuchsia also can be increased by the use of high temperature, but differences in rooting were independent of changes in leaf RWC.
Leaf water potential (LWP). relative water content (RWC), gas exchange rates and 4th-derivative spectra were measured in water-stressed and normally Irrigated plank of Totem' strawberry (Fragaria × ananassa) grown in a growth chamber. CO2 assimilation rate (A) dropped sharply when LWP decreased from -0.5 to -1.2 MPa and almost ceased as LWP fell below -1.5 MPa. There was a significant but more gradual decline of A as RWC decreased form 90% to 55%. An exponential relationship with A was observed across a wide range of LWP and RWC (Rz= 0.64, 0.86, respectively). LWP was more closely related with transpiration and leaf and stomatal conductances than with A and water use efficiency. RWC was highly correlated with all gas exchange parameters.
Under moderate water stress, younger leaves maintain higher RWC and A than older leaves. There was no relationship between LWP and leaf age.
RWC and A were both negatively correlated with peak amplitudes of Ca 684 and Ca 697 and positively correlated with Ca 693 in their 4th-derivative spectra of chlorophyll. LWP had a negative correlation with Cb 640.
Leaf water potential (LWP), relative water content (RWC), gas exchange characteristics, and specific leaf weight (SLW) were measured six hours before, during, and after water stress treatment in F. chiloensis and F. ×ananassa grown in growth chambers. The leaves of both species showed significantly lower LWP and RWC as water stress developed. F. ×ananassa had consistency lower LWP under stressed and nonstressed conditions than F. chiloensis. F. ×ananassa had higher RWC under nonstressed conditions, and its RWC decreased more rapidly under water stress than F. chiloensis. In comparison to F. ×ananassa, F. chiloensis had significantly higher CO2 assimilation rate (A), leaf conductance (LC), and SLW, but not transpiration rate (Tr), under stressed and nonstressed conditions. LC was the most sensitive gas exchange characteristic to water stress and decreased first. Later, A and stomatal conductance were reduced under more severe water stress. A very high level of Tr was detected in F. ×ananassa under the most severe water stress and did not regain after stress recovery, suggesting a permanent damage to leaf. The Tr of F. chiloensis was affected less by water stress. Severe water stress resulted in higher SLW of both species.
market tomatoes ( USDA, 1991 ). Predawn and midday leaf water potential (Ψ L ) and leaf relative water content (RWC) measurements were initiated on 7 July 2009 and 14 July 2010. Measurements of leaf RWC and Ψ L were conducted during the same time period
relative water content (RWC) was determined on leaf samples ( Barrs and Weatherley, 1962 ). Turf quality (TQ) was evaluated with a visual score that ranged from 1 to 9, where 1 = brown, necrotic plants and 9 = dense, green, and healthy grass ( Beard, 2001
, UT) that was calibrated with 0.550, 0.157, and 0.053 m solutions of NaCl of known ψ S of –2.5, –0.75, and –0.25 MPa, respectively. Relative water content. RWC was measured in the first experiment. After removing the leaf core used to determine Ψ π
determine the relative water content (RWC), electrolyte leakage, and Pro and GB contents. Measurement of soil water potential. Soil samples were collected from plants exposed to different treatments (7, 10, 14, 18, and 21 d) and from their respective control
contributed to the lower temperature extremes that occurred in 2011 compared with 2010 that permitted better growth of turfgrass sward receiving the high irrigation regime. Leaf relative water content. RWC is a measurement that indicates the physiological
: NAP (%) = 100 − [(pixels of green leaf area) / (pixels of overall plant leaf area) × 100] ( Wang et al., 2008 ). Expt. 2: Wilt status, stomatal conductance, and relative water content of CaCl 2 -treated violas. Seeds of V . cornuta ‘Sorbet XP Yellow