Short-term Effect of Uniconazole on the Water Relations and Growth of Ligustrum

Abstract

<jats:p>Growth of potted <jats:italic>Ligustrum</jats:italic> was controlled by uniconazole at 3.0 mg a.i./pot. Uniconazole inhibited growth by inducing shorter internodes with smaller diameter and by reducing secondary branching and new leaf production. As a result, the total leaf area of the treated plants was 6396 less than the control plants. The chlorophyll content of recently expanded leaves was 27% lower in treated than in control plants, even though there were no visual differences in leaf color. Leaves of treated plants also had a 28% higher stomatal density than the control. The liquid flow conductance of <jats:italic>Ligustrum</jats:italic> was 3.7 × 10<jats:sup>-14</jats:sup> m·s<jats:sup>-1</jats:sup>·Pa<jats:sup>-1</jats:sup> and was similar for plants in both treatments. Differences in daily water, use between the two treatments began to appear at the same time as differences in growth. Total water use of treated plants was 13% less than that of the control. When daily water use was normalized on a-leaf-area basis, water use between treatments was similar, suggesting that differences in total water use were primarily due to differences in leaf area. For plants in both treatments, peak sap flow rates in the main trunk ranged between 60 and 100 g·h<jats:sup>-1</jats:sup>·m<jats:sup>-2</jats:sup>. Leaf conductance, transpiration rates, and water potential were also similar for treated and control plants. Chemical name used: (E)-1-(4-chlorophenyll) -4,4, -dimethyl-2-(l,2,4-triazo1-l-y1)-l-penten-3-ol (uniconazole).</jats:p>

Relationship of Plant Growth and Actual Evapotranspiration to Irrigation Frequency Based on Management Allowed Deficits for Container Nursery Stock

“…Based on the methodology, plants in Knoxʼs (1998) research likely were maintained comparable to the 20% to 40% MAD regimes used here. Cumulative ET A for japanese ligustrum grown under well-watered conditions in 7.6-L containers, while still substantially less (18 L over 70 d; Steinberg et al, 1991), was much closer to the values reported here. Difference between cumulative ET A reported here, and those of Steinberg et al (1991) are most likely due to differences in plant size, which in the authorʼs experience is nonlinear relative to container size.…”

“…Cumulative ET A for japanese ligustrum grown under well-watered conditions in 7.6-L containers, while still substantially less (18 L over 70 d; Steinberg et al, 1991), was much closer to the values reported here. Difference between cumulative ET A reported here, and those of Steinberg et al (1991) are most likely due to differences in plant size, which in the authorʼs experience is nonlinear relative to container size. These large differences in cumulative ET A reported here underscore the importance of using separate irrigation zones for different size containers and different size plants within the same container size for water conservation.…”

Measurements of Water Use by Prairie Grasses with Heat Balance Sap Flow Gauges

“…Because grasses have limited internal plant water capacitance (Nobel and Jordan 1983), water use by range grasses as measured with sap flow gauges is nearly equivalent to transpiration and could be related directly to various environmental factors (net radiation, air saturation deficit, temperature, and wind speed) that influence plant water use. Sap flow can be summed easily over time for determining the total amount of water used by individual species in different treatments (Steinberg et al 1991, Gavloski et al 1992. In breeding and selection programs, cumulative sap flow could provide an quantitative measure of water use over the life of a grass plant that is not feasible with instantaneous measures of stomata1 conductance or transpiration (Johnson and Asay 1993).…”

Rootstock-induced Differences in Sap Flow of `Granny Smith' Apple

“…The steady-state, heat-balance technique is practical and can measure sap flow rate and sap flow accumulation over time for small woody ornamentals and trees with great precision (Cohen et al, 1993;Steinberg et al, 1989Steinberg et al, , 1990aSteinberg et al, , 1990bSteinberg et al, , 1991aSteinberg et al, , 1991bZajicek et al, 1990). Our objective was to investigate the meter (model LI-3000; LI-COR).…”