332 Mori et al.: Carbon Uptake and Air Pollution Mitigation of Different Evergreen Shrub Species ration (E); water use efficiency (WUE = A/E)] were measured at T-0 (before the onset of drought), T-1 (one day aſter imposition of drought), T-2 (three days aſter imposition of drought), T-3 (five days aſter imposition of drought), T-4 (end of partial relief), T-5 (end of experiment), using the same methods and instruments as described in Experiment 1; 2) pre-dawn water potential was measured at T-3 1) leaf gas exchange [CO2 using a Scholander type pressure bomb (PMS Instru- ments, Albany, Oregon, U.S.) between 3:00 and 5:00 am on four leaves per species, treatment, and block; 3) maximum quantum yield of PSII photo- chemistry (Fv/Fm) and chlorophyll a fluores- cence induction (OJIP) curve were performed with HANDY PEA (Hansatech Instruments Ltd, Norfolk, United Kingdom) on four leaves per spe- cies, treatment, and block (44 leaves in total); 4) drought-induced changes in growth rate were measured calculating the relative growth rate (RGR) of each species from the beginning to the end of the experiment, as described in a previous work (Fini et al. 2010). Experiment 3: Leaf Surface Accumu- lation of Trace Metals In spring 2010, 50 three-year-old shrubs of A. un- edo, E. × ebbingei, L. nobilis, L. japonicum, P. × fraseri, and V. lucidum (300 shrubs in total) were planted in a field next to a high-traffic road. Be- fore planting, soil was plowed to 40 cm. Shrubs were planted into hand-dug planting holes (as deep as the rootball and 1.5 times the width of the rootball) and irrigated as required to avoid any drought stress during the first year. Shrubs were planted to form two vegetation belts, each 30 m long and 5 m wide. These belts were parallel to a four-lane road (average daily number of vehicles was 12,000) in Pescia, Italy (N 43°52’57.7992”, E 10°40’58.0692”), and were at a distance of 1.5 m from the road verge. Distance between belts was 30 m. Twenty-five shrubs per species formed a 5 m Precipitation (mm) Wind direction Wind speed (m s-1 Temperature (°C) ) Relative humidity (RH%) 19 May – 21 June 10.80 SW 0.80 20.78 71.45 ©2016 International Society of Arboriculture assimilation (A); traspi- × 5 m section in each belt. The experimental area is located 35 km from the Ligurian Sea and the land is dedicated mainly to floricultural and resi- dential uses (Figure 1). Climate parameters for the area during the experiment are reported in Table 1. The dominant wind in the experimental plot is from the sea (west to east), thus the barriers are on the leeward side of the road (Figure 1). At plant- ing, shrubs were pruned to uniform size of 150 cm, with the exception of L. japonicum and E. × ebb- ingei which were 130 cm tall. Initial total leaf area was measured on four shrubs per species. To mea- sure leaf area, shrubs were fully defoliated and leaf fresh weight was immediately determined; 30% (in weight) of the leaves of each shrub were sub- sampled and used for the leaf area measurements, which were carried out using a RS2XA illumina- tion and camera system (Kaiser, Germany) and A3 Lightbox (G.C.L., Durham, UK) with WinDIAS soſtware (Dynamax Inc., Houston, Texas, U.S.). Each subsample (30% in weight) was then dried separately and the specific leaf area (SLA) was cal- culated on those leaves as the ratio between their area and dry weight. SLA values were then mul- tiplied per the total leaf dry weight of samples to obtain the total leaf area of each plant (Table 2). Figure 1. Arial photo of the area surrounding the experimental site. The orientation of the two vegetation belts (indicated with dark rectangle) and the main land use areas (agricul- tural and residential) are shown. Black arrow indicates north. Table 1. Meteorological data for the experimental area of the three periods prior to the 2011 samplings. Sampling periods 21 June – 03 August 11.20 SW 0.80 23.33 63.94 WSW 0.62 23.24 61.33 03 August – 04 October 80,00
September 2016
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
