HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Grantz, D. A. Articles by Shrestha, A. Search for Related Content PubMed Articles by Grantz, D. A. Articles by Shrestha, A. Agricola Articles by Grantz, D. A. Articles by Shrestha, A. Related Collections Weed Management Cotton Plant and Environment Interactions Air Pollution

Tropospheric Ozone and Interspecific Competition between Yellow Nutsedge and Pima Cotton

^a Dep. of Botany and Plant Sci. and Air Pollution Research Center, Univ. of California, Riverside, CA, and Kearney Agricultural Center, 9240 S. Riverbend Ave., Parlier, CA 93648
^b Statewide Integrated Pest Management Program, Univ. of California, Kearney Agricultural Center, 9240 S. Riverbend Ave., Parlier, CA 93648

View larger version (19K): [in a new window]   Fig. 1. Effect of ozone exposure on above-ground biomass productivity of cotton and nutsedge. Open symbols represent each species grown alone; closed symbols represent the average of all levels of nutsedge competition (All:1). Statistical differences between means within a line are indicated by different lowercase letters and symbols indicating the level of significance. Statistical differences between lines are indicated by uppercase letters and symbols indicating the level of significance. ** indicates P 0.01.

View larger version (25K): [in a new window]   Fig. 2. Effect of nutsedge density (nutsedge-cotton ratio) on (A) shoot biomass and on (B) the inverse of shoot biomass of cotton a teach level of ozone exposure (LO3, MO3, and HO3). In (B), the slope of each line is interpreted as a competition coefficient (c).Mean separation for data points, lines, and values of c as in Fig. 1. * and ** indicate P 0.05 and P 0.01, respectively.

View larger version (25K): [in a new window]   Fig. 3. Effect of ozone exposure on shoot growth of cotton grown alone (0:1; open symbols) or averaged over all population ratios of nutsedge–cotton (All:1; closed symbols), expressed as (A) main stem length, (B) leaf area, and (C) number of leaves. Insets present the effects of nutsedge competition on the same measures of shoot growth at each level of ozone exposure (LO3, MO3, and HO3). Mean separation as in Fig. 1. ** indicates P 0.01.

View larger version (24K): [in a new window]   Fig. 4. Effect of ozone exposure on (A) leaf chlorophyll concentration (SPAD units) of cotton sampled at different insertion levels: upper, mid-, and lower canopy (open symbols), or on nutsedge grown alone (solid squares), on (B) net carbon assimilation, and (C) stomatal conductance to water vapor of young exposed leaves of nutsedge (open squares) and cotton (open circles), grown alone. Mean separation as in Fig. 1. ** indicates P 0.01, and indicates P 0.10.

View larger version (24K): [in a new window]   Fig. 5. Effect of ozone exposure of the shoot on (A) below-ground biomass productivity of cotton (circles) and nutsedge (squares) grown alone and on the combined biomass of one plant of each species grown in direct competition (solid triangles), and (B) on the reproductive effort of nutsedge grown alone (1:0; open squares) or averaged over all population ratios (All:1; solid squares), expressed as the number of reproductive structures per plant. Mean separation as in Fig. 1, and indicates P 0.10.

View larger version (16K): [in a new window]   Fig. 6. Effect of ozone exposure on the respiratory activity of fine roots of cotton (circles) and nutsedge (squares). Mean separation as in Fig. 1.