Life Sciences Commons^™

Field Evaluation Of Herbicides On Rice 2004, Brian V. Ottis, Ronald E. Talbert, Andrew T. Ellis

Arkansas Agricultural Experiment Station Research Series

Herbicide evaluation studies on rice were conducted in 2004 at the Rice Research and Extension Center near Stuttgart, AR, in an effort to evaluate new herbicides, herbicide mixtures, and their application timings for weed control and crop tolerance. Results of these studies, in part, provide useful information to producers, fellow researchers, and the Crop Protection Industry for the potential use of new herbicide programs for successful rice production in Arkansas.

Dynamic Response Indicators Of Heat Stress In Shaded And Non-Shaded Feedlot Cattle, Part 1: Analyses Of Indicators, T. M. Brown-Brandl, R. A. Eigenberg, J. A. Nienaber, G. Leroy Hahn

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Heat stress in feedlot cattle can cause decreases in feed intake and growth, and in extreme cases may result in death. Providing shade during hot weather has shown inconsistent results, reducing direct and indirect losses in some areas of the United States, but not in others. The objectives of this study were to evaluate the dynamic responses of feedlot cattle to environmental conditions with and without access to shade, and to determine the most appropriate physiological measurement for monitoring feedlot cattle during hot weather as a guide for improved management. Eight crossbred steers (initially weighing 294.7±10.8 kg) were randomly assigned …

Soil Surveys: A Window To The Subsurface, Douglas A. Wysocki, P. J. Schoeneberger, H. E. Lagarry

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Soils and underlying parent materials form a continuous system we must understand and manage in total. Numerous concerns (e.g., water quality, on-site waste disposal, landfill placement, and nutrient or pesticide movement) require an integrated knowledge and understanding of soil, the soil-to-substratum transition, and the deeper substratum. Soil C-horizons can exceed the thickness of the overlying A and B-horizons and contain unique morphological properties. The subsolum including C-horizons receives less descriptive emphasis than upper soil horizons. Soil scientists map and classify soils mainly on A and B-horizon properties. Soil forming and hydrologic processes that impart morphological features, however, extend considerably below …

Impact Of Reduced Lignin On Plant Fitness, J. F, Pedersen, K. P. Vogel, D. L. Funnell

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Lignin content of crop plants has been reduced by traditional plant breeding, natural and induced mutations, and insertion of transgenes. The effects of these genes and associated lower lignin content have been examined in terms of agricultural fitness or with regard to economically harvestable yields of useful plant products, or, in the case of some perennial species, survivability over multiple years. In general, crop yields are depressed by significant reductions in lignin content. Other negative effects observed in plants with lowered lignin contents include lodging and reduction of long-term survival of some perennial species. However, the interactions of genes involved …

Why Is Maize A Sacred Plant? Social History And Agrarian Change On Sumba, Cynthia Twyford Fowler

Faculty Scholarship

Why has maize, a plant with origins in the New World, become ritually important in an indigenous Southeast Asian religion? While environmental conditions and agricultural economics are key determinants of everyday resource management practices in insular Southeast Asia, it is necessary to consider ethnic identity, political economy, and social structure in order to understand the religious significance of natural resources in contemporary society. Linguistic, cosmological, and horticultural data are combined with an analysis of local perceptions of culture and environment. This information is used to explain the transformation of an introduced plant into an indigenous sacrament. Ethnographic data, including a …

Arkansas Cotton Variety Test 2004, Fred M. Bourland, B. S. Brown, J. M. Hornbeck, R. C. Doherty, W. C. Robertson

Arkansas Agricultural Experiment Station Research Series

The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant.

Colonization Of Gnotobiotic Piglets By A Luxs Mutant Strain Of Escherichia Coli O157:H7, Dianna M. Jordan, Vanessa Sperandio, James B. Kaper, Evelyn A. Dean-Nystrom, Harley W. Moon

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Gnotobiotic piglets inoculated with Escherichia coli O157:H7, its luxS mutant derivative, or nonpathogenic E. coli were evaluated for attaching and effacing lesions. Although no differences in clinical symptoms were seen between pigs inoculated with the parent and those inoculated with the luxS mutant, the luxS mutant-inoculated pigs had a lower frequency of attaching and effacing lesions in the spiral colon than parent strain-inoculated pigs.

Intsormil 2005 Annual Report, John M. Yohe, Kimberly Christiansen, Joan Frederick

INTSORMIL Impacts and Bulletins

The 2005 INTSORMIL Annual Report presents the progress and notable achievements by the SorghumiMillet CRSP during the period of July 1, 2004 - June 30, 2005. These results are an outcome of partnerships between scientists at six U.S. Land Grant Universities (Kansas State University, Mississippi State University, University of Nebraska, Purdue University, Texas A&M University and West Texas A&M University) and scientists of the Agricultural Research Service of the U.S. Department of Agriculture at Tifton, Georgia and National Agricultural Research Systems (NARS) and National Universities in nineteen countries in Central America, West Africa, East Africa and Southern Afflca.

Agricultural research …

Molecular Evolution Of Herbicide Resistance To Phytoene Desaturase Inhibitors In Hydrilla Verticillata And Its Potential Use To Generate Herbicide-Resistant Crops, R. S. Arias, Michael D. Netherland, Brian E. Scheffler, Atul Puri, Franck E. Dayan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Hydrilla [Hydrilla verticillata (Lf) Royle] is one of the most serious invasive aquatic weed problems in the USA. This plant possesses numerous mechanisms of vegetative reproduction that enable it to spread very rapidly. Management of this weed has been achieved by the systemic treatment of water bodies with the herbicide fluridone. At least three dioecious fluridone-resistant biotypes of hydrilla with two- to fivefold higher resistance to the herbicide than the wild-type have been identified. Resistance is the result of one of three independent somatic mutations at the arginine 304 codon of the gene encoding phytoene desaturase, the molecular target …

Registration Of ‘Arrowsmith’ Hard White Winter Wheat, Robert A. Graybosch, C.J. Peterson, P. Stephen Baenziger, Lenis Alton Nelson, B.B. Beecher, D. D. Baltensperger, J.M. Krall

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

‘Arrowsmith’ (Reg. no. CV-969, PI 633911) hard white winter wheat (Triticum aestivum L.) was developed cooperatively by USDA-ARS, the Nebraska Agricultural Experiment Station, and the Wyoming Agricultural Experiment Station. Arrowsmith is adapted to dryland environments in western Nebraska and eastern Wyoming. It was released on the basis of its white grain color, medium-long coleoptile length, and tall plant height, all desirable features for wheat grown on dryland sites in the Nebraska Panhandle and eastern Wyoming.

Arrowsmith was derived from the cross KS87809-10/‘Arapahoe’, made in 1993. KS87809-10 is an experimental hard winter wheat from Kansas State University with the pedigree …

Evaluation Of Oviposition Substrates And Organic Infusions On Collection Of Culex In Florida, Sandra Allan, Ulrich R. Bernier, David Kline

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Gravid mosquito traps are commonly used for both arbovirus surveillance and population surveillance of mosquitoes of the genus Culex. Oviposition substrates, used as baits in these traps, were tested against Culex under laboratory and field conditions. In the laboratory all substrates tested as 1% and 10% dilutions in 2-choice bioassays against female Cx. quinquefascians were significantly more effective than well water controls in eliciting oviposition. Strongest responses were to dilutions of dairy effluent, followed by larval water and infusions of alfalfa hay, alfalfa pellets, Bermuda hay, oak leaves, and Typha leaves, with lowest responses to cow manure infusion. …

Comparison Of Contact And Spatial Repellency Of Catnip Oil And N,N-Diethyl-3-Methylbenzamide (Deet) Against Mosquitoes, Ulrich R. Bernier, Kay D. Furman, Daniel L. Kline, Sandra A. Allan, Donald R. Barnard

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Nepetalactone, the primary component of catnip oil, was compared with the repellent N,N-diethyl-3-methylbenzamide (deet) for its ability to affect the host-seeking ability of Aedes aegypti (L.). A triple cage olfactometer was used to bioassay each substance and to assess its attraction inhibition (spatial repellent) attributes when combined with the following attractants: carbon dioxide, acetone, a blend of L-lactic acid and acetone, and human odors. Repellent tests were conducted with each substance against female Ae. aegypti, Anopheles albimanus Weidemann, and Anopheles quadrimaculatus Say. Catnip oil and deet were both weakly attractive to Ae. aegypti, catnip oil was the better spatial …

Modeling Bacterial Udp-Hexnac: Polyprenol-P Hexnac-1-P Transferases, Neil P. Price

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Protein N-glycosylation in eukaryotes and peptidoglycan biosynthesis in bacteria are both initiated by the transfer of a D-N-acetylhexosamine 1-phosphate to a membrane-bound polyprenol phosphate. These reactions are catalyzed by a family of transmembrane proteins known as the UDP-D-N- acetylhexosamine: polyprenol phosphate D-N-acetylhexosamine 1-phosphate transferases. The sole eukaryotic member of this family, the D-N-acetylglucosamine 1-phosphate transferase (GPT), is specific for UDP-GlcNAc as the donor substrate and uses dolichol phosphate as the membrane-bound acceptor. The bacterial translocases, MraY, WecA, and WbpL, utilize undecaprenol phosphate as the acceptor substrate, but differ in their specificity for …

A Modified Molybdenum Blue Method For Orthophosphate Determination Suitable For Investigating Enzymatic Hydrolysis Of Organic Phosphates, Zhongqi He, C. Wayne Honeycutt

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In characterizing organic phosphorus (P_o) by phosphatase hydrolysis, the quantity of hydrolyzable P_o is represented by the difference in orthophosphate [i.e., inorganic P (P_i)] determined after and prior to enzymatic incubation. Therefore, precise determination of P_i is of major importance for accurate application of the enzymatic hydrolysis approach. The strong acid conditions required for conventional molybdenum blue methods interferes with P_i determination due to rapid hydrolysis of labile P_o and precipitation of enzymes (proteins). The molybdenum blue method of Dick and Tabatabai in 1977 reduced errors pertaining to nonenzymatic hydrolysis of P …

Weed Suppression By Deleterious Rhizobacteria Is Affected By Formulation And Soil Properties, Robert E. Zdor, Carlene M. Alexander, Robert J. Kremer

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Deleterious rhizobacteria (DRB) suppress weed growth in field tests and are considered potential weed biological control agents. This study compared the relative inhibitory action of the DRB Pseudomonas fluorescens strain G2-11 in different formulations, corn gluten meal (CGM), and semolina flour, toward wheat (Triticum aestivum L.), green foxtail (Setaria viridis (L.) Beauv.), and velvetleaf (Abutilon theophrasti Medik) seeds and seedlings in soil assays. Strain G2-11 successfully established in semolina flour as an inoculum formulation but was incompatible with CGM presumably because of antibacterial factors present. The effect of DRB and plant products on seed germination and plant …

Effect Of Oxygen Management On Culture Performance Of Channel Catfish In Earthen Ponds, Eugene L. Torrans

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Aeration allows for higher feeding rates and increased production of channel catfish Ictalurus punctatus in intensive and semi-intensive aquaculture systems. However, the effect of specific dissolved oxygen (DO) concentrations on various production parameters remains unknown. The purpose of this 2-year study was to determine the effect of daily minimum DO concentration on channel catfish production. Six 0.1-ha ponds were each equipped with three 0.37-kW (0.5-hp) aerators and one 0.37-kW circulator. Dissolved oxygen concentrations were monitored and recorded with a commercial oxygen monitor that also controlled aeration. During both years, aeration in the high-oxygen treatment was initiated when the DO concentration …

Prevalence Of Pathogenic Yersinia Enterocolitica Strains In Pigs In The United States, Saumya Bhaduri, Irene V. Wesley, Eric J. Bush

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Yersinia enterocolitica is considered an important food-borne pathogen impacting the pork production and processing industry in the United States. Since this bacterium is a commensal of swine, the primary goal of this study was to determine the prevalence of pathogenic Y. enterocolitica in pigs in the United Sates using feces as the sample source. A total of 2,793 fecal samples were tested for its presence in swine. Fecal samples were collected from late finisher pigs from 77 production sites in the 15 eastern and midwestern pork-producing states over a period of 27 weeks (6 September 2000 to 20 March 2001). …

Abundance Of Plodia Interpunctella (Hubner) And Cadra Cautella (Walker) Infesting Maize Stored On South Carolina Farms: Seasonal And Non-Seasonal Variation, Richard T. Arbogast, Shahpar R. Chini

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Seasonal trends and short-term fluctuations in abundance of Plodia interpunctella (Hubner) and Cadra cautella (Walker) infesting maize stored on two South Carolina farms were studied during three storage seasons (September 1990–June 1993). Coils of corrugated paper placed on the grain surface were used to trap mature larvae seeking pupation sites. Temperatures in the grain (18-cm-deep) and in the bin headspace were recorded hourly, and grain moisture content was measured weekly. Weekly mean numbers of moth larvae, and adults of two natural enemies, trapped in the coils were used for tracking changes in their abundance over time. The most significant findings …

Apoplastic Redox Metabolism: Synergistic Phenolic Oxidation And A Novel Oxidative Burst, C. Jacyn Baker, Daniel P. Roberts, Norton M. Mock, Bruce D. Whitaker, Kenneth L. Deahl, Andrey A. Aver'yanov

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The plant apoplast is an important mediator of communication between the cell cytoplasm and its surroundings. Plant cell suspensions offer a convenient model system to gain insight into apoplastic physiology. Here, we describe a novel phenomenon that took place when two naturally occurring phenolics were added together to either soybean or tobacco cell suspensions. Acetosyringone (AS) and/or hydroxyacetophenone (HAP), phenolics found in the extracellular/apoplast of tobacco cells, were added to soybean or tobacco cell suspensions undergoing an oxidative burst. Individually, AS appeared to be utilized as a typical peroxidase substrate to scavenge hydrogen peroxide, while HAP was utilized at a …

Biocontrol Agents Applied Individually And In Combination For Suppression Of Soilborne Diseases Of Cucumber, Daniel P. Roberts, Scott M. Lohrke, Susan L. F. Meyer, Jeffry S. Buyer, John H. Bowers, C. Jacyn Baker, Wei Li, Jorge T. De Souza, Jack A. Lewis, Soohee Chung

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The soilborne pathogens Rhizoctonia solani, Pythium ultimum, and Meloidogyne incognita can cause severe economic losses to field- and greenhouse-grown cucumber. A collection of bacterial isolates and isolates GL3 and GL21 of Trichoderma virens were screened for suppression of diseases caused by these pathogens. T. virens isolates GL3 and GL21 provided the most effective suppression of damping-off caused by R. solani in greenhouse bioassays. Burkholderia ambifaria BC-F, B. cepacia BC-1, and Serratia marcescens N1-14 also provided significant suppression of R. solani relative to the pathogen check in some experiments. T. virens isolates GL3 and GL21 and S. marcescens isolates …

Post-Release Evaluation Of Biological Control Of Bemisia Tabaci Biotype ‘‘B’’ In The Usa And The Development Of Predictive Tools To Guide Introductions For Other Countries, John A. Goolsby, Paul J. Debarro, Alan A. Kirk, Robert W. Sutherst, Luis Canas, Matthew A. Ciomperlik, Peter C. Ellsworth, Juli R. Gould, Diana M. Hartley, Kim A. Hoelmer, Steven E. Naranjo, Mike Rose, William J. Roltsch, Paul A. Ruiz, Charles H. Pickett, Don C. Vacek

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Climatic matching and pre-release performance evaluation were useful predictors of parasitoid establishment in a retrospective analysis of a classical biological control program against Bemisia tabaci biotype ‘‘B’’ in the USA. Laboratory evaluation of 19 imported and two indigenous parasitoid species in quarantine on B. tabaci showed that the Old World Eretmocerus spp, had the highest attack rate. The climate matching program CLIMEX was used to analyze the establishment patterns of five Old World Eretmocerus spp. introduced to the Western USA. The top matches ±10% for the climate of the area of introduction and origin of the introduced parasitoids always included …

Induction Of Redox Sensitive Extracellular Phenolics During Plant–Bacterial Interactions, C. Jacyn Baker, Bruce D. Whitaker, Daniel P. Roberts, Norton M. Mock, Clifford P. Rice, Kenneth L. Deahl, Andrey A. Aver'yanov

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

This study focuses on the transient and complex nature of phenolics that accumulate in the extracellular environment of plant suspension cells during the first few hours of the interaction between these plant cells and bacterial pathogens. Using suspension cells of Nicotiana tabacum we identified four acetophenones and four hydroxycinnamic acid amides that accumulate in this extracellular environment. Treatment of the suspension cells with isolates of the plant pathogen Pseudomonas syringae or heat-killed bacteria increased elicitation of extracellular phenolics and changed the composition of the compounds that accumulated. These phenolics were sensitive to oxidative stress; when suspension cells were treated with …

Carbaryl Resistance In Mexican Strains Of The Southern Cattle Tick (Acari: Ixodidae), Andrew Y. Li, Ronald B. Davey, John E. George

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Susceptibility to carbaryl in six Mexican strains of the southern cattle tick, Boophilus microplus (Canestrini), was evaluated with the Food and Agricultural Organization larval packet test. Tick strains from the cattle fever tick quarantine zone in Texas were more susceptible to carbaryl than to coumaphos or diazinon. Compared with the susceptible reference (Gonzalez) strain, Mexican tick strains demonstrated 10.9Ð59.5-fold resistance to carbaryl. SigniÞcant cross-resistance was found between carbaryl and the organophosphate acaricides coumaphos and diazinon. Bioassay results with synergists suggested that metabolic detoxification mechanisms did not play a major role in carbaryl resistance. Resistance to carbaryl was likely conferred by …

Insect Transmission Of Plant Pathogens, Rodrigo P. P. Almeida, Astri Wayadande, Todd Shelly

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Much of biological research conducted today is multidisciplinary, partly because of the availability of ever simpler to use molecular tools and the realization that ecological systems are complex and multitrophic. Although there is a general trend toward academic specialization and cooperation, some fields still require that scientists be aware of the “bigger picture.” We consider that the study of insect-transmitted plant pathogens is one of those fields, where insect, pathogen, and plant are inseparably linked. In this triangle of interactions, researchers focus their interests on questions at the molecular and cellular to epidemiological levels. Throughout the years, plant vector entomologists …

Maintenance Of A Narrow Host Range By Oxyops Vitiosa; A Biological Control Agent Of Melaleuca Quinquenervia, G. S. Wheeler

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Host range expansion in insect herbivores is often thought to be mediated by several factors, principal among them are secondary plant metabolites. In weed biological control, the host range of a prospective agent is one of the most important considerations in its implementation. Extensive host testing tests seek to determine the behavioral acceptance and nutritional value of different test plant species to the potential agent. A list of test plants is compiled that comprises species that are close taxonomic relatives of the target weed plus other species of economic or ecologic importance. The host testing of the Melaleuca quinquenervia biological …

Postweaning Performance Of Hair And Wool Sheep And Reciprocal-Crosses On Pasture And In Feedlot, M. A. Brown, H. S. Mayeux

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Lambs from three diallel-mating plans (Dorset-St. Croix, n=140; Rambouillet-Gulf Coast, n=80; Katahdin-Suffolk, n=78) and a terminal-cross mating plan (Suffolk rams mated to Dorset, St. Croix and reciprocal-cross ewes, n=100) were used to evaluate postweaning grazing performance of traditional meat breeds and tropically adapted breeds of sheep.

Risk And Ethics In Biological Control, Ernest S. Delfosse

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

All introduced natural enemies present a degree of risk to nontarget species. Since most biological control programs use relatively host-specific natural enemies, the risk to nontarget species is generally very low, particularly from biological control of weeds, which uses extensively tested and validated host-specificity testing procedures to predict risk. However, many of the published comments about risks of biological control are superficial or misleading, often inappropriately lumping risk from all taxa of agents as “the risk of biological control,” and ignore the potential benefits, rather than dealing with species-by-species risk and benefits. Particularly confounding accurate predictions is the common mixing …

Seasonal Acceptance Of Fourwing Saltbush By Sheep When Crested Wheatgrass Is The Alternative, Christine W. Royer, R. D. Horrocks, Val J. Anderson, Stephen B. Monsen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Many sagebrush-grass ranges have been seeded to crested wheatgrass [Agropyron desertorum (Fischer ex Link) Shultes]. These ranges are generally nutritionally inadequate for sheep (Ovis aries L.), except for short grazing periods in the spring and fall. To increase production and diversity, particularly crude protein for late-season grazing, fourwing saltbush [Atriplex canescens (Pursch.) Nutt.] was planted in an existing stand of crested wheatgrass. Quantification of sheep forage preferences on these improved ranges aids in determining the length of the grazing season and the extent to which shrubs provide the supplemental nutrition required. This seasonal grazing study was conducted …

Integration Of Co 2 Flux And Remotelysensed Data For Primary Production And Ecosystem Respiration Analyses In The Northern Great Plains: Potential For Quantitative Spatial Extrapolation, Tagir G. Gilmanov, Larry L. Tieszen, Bruce K. Wylie, Larry B. Flanagan, Albert B. Frank, Marshall R. Haferkamp, Tilden P. Meyers, Jack A. Morgan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Aim Extrapolation of tower CO₂ fluxes will be greatly facilitated if robust relationships between flux components and remotely sensed factors are established. Long-term measurements at five Northern Great Plains locations were used to obtain relationships between CO₂ fluxes and photosynthetically active radiation (Q), other on-site factors, and Normalized Difference Vegetation Index (NDVI) from the SPOT VEGETATION data set.

Herbivory Alters Resource Allocation And Compensation In The Invasive Tree Melaleuca Quinquenervia, P. D. Pratt, M. B. Rayamajhi, T. K. Van, T. D. Center, P. W. Tipping

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The Australian native Melaleuca quinquenervia is highly invasive in the Florida Everglades, U.S.A., where it experiences limited competition or herbivory from native species, making it a likely candidate for compensation. The introduced biological control agent Oxyops vitiosa feeds exclusively on the seasonal flushes of developing foliage at branch apices, which represents ~ 15% of the total foliar biomass.