You are looking at 21 - 30 of 29,729 items for

  • Refine by Access: All x
Clear All
Open access

Celina Gómez, Megha Poudel, Matias Yegros, and Paul R. Fisher

The objectives were to characterize and compare shrinkage (i.e., transplant loss) and growth of tissue-cultured blueberry (Vaccinium corymbosum) transplants acclimated in greenhouses or indoors under 1) different photosynthetic photon flux densities (PPFDs) (Expt. 1); or 2) spectral changes over time using broad-spectrum white (W; 400 to 700 nm) light-emitting diodes (LEDs) without or with red or far-red (FR) radiation (Expt. 2). In Expt. 1, ‘Emerald’ and ‘Snowchaser’ transplants were acclimated for 8 weeks under PPFDs of 35, 70, 105, or 140 ± 5 µmol·m‒2·s‒1 provided by W LED fixtures for 20 h·d−1. In another treatment, PPFD was increased over time by moving transplants from treatment compartments providing 70 to 140 µmol·m‒2·s‒1 at the end of week 4. Transplants were also acclimated in either a research or a commercial greenhouse (RGH or CGH, respectively). Shrinkage was unaffected by PPFD, but all transplants acclimated indoors had lower shrinkage (≤4%) than those in the greenhouse (15% and 17% in RGH and CGH, respectively), and generally produced more shoot and root biomass, regardless of PPFD. Growth responses to increasing PPFD were linear in most cases, although treatment effects after finishing were generally not significant among PPFD treatments. In Expt. 2, ‘Emerald’ transplants were acclimated for 8 weeks under constant W, W + red (WR), or W + FR (WFR) radiation, all of which provided a PPFD of 70 ± 2 μmol·m−2·s−1 for 20 h·d−1. At the end of week 4, a group of transplants from WR and WFR were moved to treatment compartments with W (WRW or WFRW, respectively) or from W to a research greenhouse (WGH), where another group of transplants were also acclimated for 8 weeks (GH). Shrinkage of transplants acclimated indoors was also low in Expt. 2, ranging from 1% to 4%. In contrast, shrinkage of transplants acclimated in GH or under WGH was 37% or 14%, respectively. Growth of indoor-acclimated transplants was generally greater than that in GH or under WGH. Although growth responses were generally similar indoors, plants acclimated under WFR had a higher root dry mass (DM) and longer roots compared with GH and WGH.

Open access

Eric T. Stafne, Jenny B. Ryals, and Barbara J. Smith

White drupelet disorder (WDD) in blackberry (Rubus subgenus Rubus) is an abiotic condition resulting from a cultivar and environment interaction. Although high temperatures and light intensities have been implicated, little is known why this disorder manifests. Other factors, such as overall plant stress, may be contributing influences. In this study, three treatments were applied to examine whether the addition of nitrogen (N) can reduce WDD on ‘Sweetie Pie’ erect blackberry over three seasons. An initial 50 lb/acre (56.0 kg⋅ha–1) N was applied to all plots at budbreak. Two additional N application treatments of 100 kg⋅ha–1 were applied at one time (1×) or five, 20-kg⋅ha–1 applications (5×), spaced 1 week apart for 5 weeks starting at bloom. One control treatment of no additional N (0×) was also included. Berries were harvested and weighed as a total, then berries with white drupelets were separated out and weighed. The two values were divided to create a proportion and were then multiplied by 100 to determine the percentage. Nitrogen application decreased the percentage of white drupelet berries from 13.0% (control) to 10.0% (one additional application) and 9.1% (five additional applications). WDD for the 0× treatment correlated negatively to maximum high daytime temperatures during May (r = –0.58, P = 0.03) over the three seasons. Occurrence of white drupelets by treatments 0×, 1×, and 5× correlated significantly with the cumulative number of rainfall events (r = 0.49, 0.47, and 0.46, respectively). Leaf chlorophyll index and photosynthesis measurements were unaffected by treatment. Although it is likely that multiple factors are involved in the development of white drupelets, additional N may reduce the problem.

Open access

Tengfei Pan, Peibin Huang, Jianwen Ye, Dongming Pan, Zhijun Fu, Heli Pan, Zhixiong Guo, Wenqin She, and Yuan Yu

Open access

Coleman L. Etheredge and James DelPrince

Retail florists in the United States were surveyed from Oct. to Nov. 2020 to document business practices and innovative approaches to marketing, designing, and delivering flowers during Mar. to Sept. 2020 of the coronavirus disease (COVID-19) pandemic. Slightly less than half of the responding florists (45.0%) closed operations for an average of 31 to 60 days (15.6%). City or county COVID-19 restrictions caused 34% to close their storefronts to customers. Nearly all offered no-contact delivery service. Approximately one-third of these florists used social media marketing consisting of still images and video posts, and a similar number offered no-contact shopping options. Two-thirds of the florists made no changes to the way they designed flowers (60.6%). Event-oriented stores reorganized their business models and sought daily work to replace postponed or canceled wedding orders. Three-fourths of the florists who terminated employees because of shutdowns hired or planned to rehire all terminated employees.

Open access

Fahed A. Al-Mana, Abdullah M. Algahtani, Yaser H. Dewir, Majed A. Alotaibi, Mohammed A. Al-Yafrsi, and Khalid M. Elhindi

Freshwater resources are being rapidly depleted because of the increased demand resulting from exponential world population growth and the effects of climate change, especially in arid and semiarid regions (e.g., Saudi Arabia). The present study aimed to examine the changes in growth and inflorescence production of snapdragon (Antirrhinum majus L.) plants in response to irrigation with saline or magnetized water, in addition to application of inorganic and/or organic soil amendments. Three different water types—tap water, magnetized saline water, and nonmagnetized saline water—were used to irrigate A. majus plants with or without soil amendments consisting of ferrous sulfate (Fe2SO4) and/or peatmoss. Irrigation with magnetized saline water adversely affected vegetative growth, inflorescence production, mineral contents, and survival rates of A. majus plants as compared with irrigation with tap water or magnetized saline water. Nevertheless, compared with unmagnetized saline water treatment, magnetizing nonmagnetized saline water before irrigation significantly improved water characteristics and plant growth and survival. Moreover, the addition of inorganic or organic soil amendments enhanced the growth of A. majus plants regardless of irrigation water type. Interestingly, the combination of irrigating with magnetized saline water and soil amendments (Fe2SO4 and peatmoss) significantly enhanced the growth of A. majus plants to a level that was comparable to that of control plants irrigated with tap water without soil amendments. Magnetization improved water quality and increased plants’ ability to absorb water and nutrients from soil solution. The utilization of magnetized saline water for irrigating food and forage crops either alone or in combination with soil amendments has potential benefits that warrant further research.

Full access

Shivani Kathi, Catherine Simpson, Alinna Umphres, and Greta Schuster

In arid and semi-arid climates, water scarcity and nutrient availability are major constraints for food production. Excess fertilization to make up for the limited nutrient availability in dry soils leads to nitrogen runoff and groundwater contamination. Reducing nitrogen leaching into surface water while providing adequate nutrition remains a major challenge. Superabsorbent polymers (SAPs) can reduce water loss and improve nutrient retention and therefore minimize leaching and increase crop yields. SAPs are made from petroleum or natural products, but plant-based SAPs have been gaining popularity because they have fewer long-term effects on the environment. However, there is little known about how SAPs made from cornstarch effect plant growth and production in tomatoes. So, we evaluated total nitrogen and water retention in SAP-treated soils and evaluated their effects on growth and development of tomatoes (Solanum lycopersicum). Soils were amended with different rates of cornstarch-based SAP (i.e., 0 kg SAP, 0 kg SAP+N, 0.5 kg SAP+N, 1 kg SAP+N, 1.5 kg SAP+N, and 2 kg SAP+N). Results indicate that the mean volume of water and nitrates retained in the soils amended with cornstarch-based SAPs increased with increasing rate of SAP. The treatment containing the highest dose (i.e., 2 kg SAP) decreased the amount of leachate and nitrates from soil 79.34% and 93.11% at 3 days after fertilization (DAF) and 78.84% and 81.58% at 9 DAF in comparison with the soil-only and fertilizer-only treatments, respectively. The results also indicate cornstarch-based SAP significantly improved plant growth and yield parameters compared with the treatments without SAP. Furthermore, the greatest number of leaves, flowers, fruits, and dry matter production were found in the 1-kg SAP treatment. Therefore, application of cornstarch-based SAPs can improve tomato production in times of drought stress by retaining more water and nutrients in the active rooting zone and can reduce environmental pollution by reducing nitrogen runoff.

Open access

Stephen B. Prentice and Tina M. Waliczek

The attention restoration theory suggests that directed attention is subject to fatigue, and the presence of nature and natural environments allows recovery from that fatigue, consequently improving cognitive function. The purpose of this study was to investigate whether the mental processes of memory and reasoning were enhanced when exercised concurrently in a natural environment outdoors vs. an artificial environment such as an indoor classroom or lecture hall. Three hundred and eighty degree-seeking students at Texas State University were tested using modified forms of the Sentence Repetition Test and the California Verbal Learning Test to test verbal memory and a modified form of the Wechsler Adult Intelligence Scale-IV Matrix Reasoning Test to evaluate nonverbal reasoning/fluid intelligence. Half of the subjects (190) were tested in their classroom at the regularly scheduled class time or one located in the same building at a predetermined date and time. Half of the subjects (190) were tested in an outdoor garden classroom at a predetermined date and time. No significant difference was found to exist between in either the memory or reasoning scores of the two groups. However, comparisons of subjects in the same demographic categories produced one significant difference. Students classified as seniors (P = 0.035) who were tested in the natural environment performed significantly better on the Sentence Repetition Test compared with those tested in the artificial environment. Research generally supports the premise that exposure to nature or natural environments can have beneficial effects on physical and mental health and also improve cognitive function. Further studies should possibly include more than one meeting time and additional testing time for participants to sit and observe in the natural vs. artificial environment before testing.

Open access

Martina Göttingerová, Michal Kumšta, Eliška Rampáčková, Tomáš Kiss, and Tomáš Nečas

The apricot is attractive for several reasons, with the most important being the harvest period and the significant amount of contained substances that positively affect human health. This report discusses the identification and quantification of phenolic substances in 15 selected apricots. The following 14 phenolic compounds were identified: 4aminobenzoic acid, chlorogenic acid, cinnamic acid, flavonols quercetin and quercitrin, isoquercetin (quercetin-3-β-D-glucoside), rutin, resveratrol, vanillin, phloridzin, phloretin, epicatechin, catechin, and transpiceid. Significant amounts of phytochemicals found in apricot fruits are chlorogenic acid [0.69–21.94 mg/100 g fresh weight (FW)], catechin (0.55–10.75 mg/100 g FW), epicatechin (0.04–13.52 mg/100 g FW), and rutin (1.49–20.44 mg/100 g FW). Rutin and chlorogenic acid were the dominant compounds found in the studied set of cultivars. Furthermore, other important analytical properties of fruits (total acids, vitamin C, total content of phenolic substances, flavonoids, antioxidant capacity, and carotenoids) were also determined.

Open access

Yang Hu, Chao Gao, Quanen Deng, Jie Qiu, Hongli Wei, Lu Yang, Jiajun Xie, and Desheng Liao

Petalized anther abortion is an important characteristic of male sterility in plants. The male sterile plants (HB-21) evincing petalized anther abortion previously discovered in a clone population of the Camellia oleifera cultivar Huashuo by our research group were selected as the experimental material in this study. Using plant microscopy and anatomic methods and given the correspondence between external morphology and internal structure, we studied the anatomic characteristics of petalized anther abortion (with a fertile plant as the control group) in various stages, from flower bud differentiation to anther maturity, in hopes of providing a theoretical basis for research on and applications of male sterile C. oleifera plants, a new method for the selection of male sterile C. oleifera cultivars, and improvements in the yield and quality of C. oleifera. In this study, the development of anthers in C. oleifera was divided into 14 stages. Petalized anther abortion in male sterile plants was mainly initiated in the second stage (the stage of sporogenous cells). Either the petalized upper anther parts did not form pollen sacs, or the entire anthers did not form pollen sacs. The lower parts of some anthers could form deformed pollen sacs and develop, and these anthers could be roughly divided into two types: fully and partially petalized anthers. Abnormal callose and the premature degradation of the tapetum occurred in the pollen sacs formed by partially petalized anthers during the development process, resulting in the absence of inclusions in the pollen grains formed. Small quantities of mature pollen grains withered inward from the germinal furrows, exhibiting obvious abortion characteristics. The relative in vitro germination rate of the pollen produced by the partially petalized anthers of sterile plants was 11.20%, and the relative activity of triphenyltetrazolium chloride was 3.24%, while the fully petalized anthers did not generate pollen grains. Either the petalized anthers in male sterile plants did not produce pollen, or the vitality of the small amounts of pollen produced by sterile plants was very low compared with that of fertile plants. Such male sterile plants could be used to select correct clones and have good prospects for application in production.

Open access

Bao-Zhong Yuan, Zhi-Long Bie, and Jie Sun

Cucumber (Cucumis sativus L.) is an economically important vegetable crop that is cultivated worldwide. The current study aimed to identify and analyze the 2030 articles and review article about cucumber research from the horticulture category of the VOS viewer Web of Science. Bibliometric data were analyzed by bibliometric science mapping and visualization tools. Articles mainly written in English (1884; 92.81%) were from 5630 authors, 80 countries or territories, and 1094 organizations; they were published in 46 journals and book series. The top five core journals are Scientia Horticulturae (337; 16.60%), HortScience (265; 13.05%), Journal of the American Society for Horticultural Science (239; 11.77%), European Journal of Plant Pathology (195; 9.61%), and Horticulture Journal (Journal of the Japanese Society for Horticultural Science) (157; 7.73%). These journals each published more than 157 articles. The top five countries and regions were the United States, People’s Republic of China, Japan, South Korea, and India. The top five organizations were the University of Wisconsin, North Carolina State University, U.S. Department of Agriculture–Agricultural Research Service, Michigan State University, and Nanjing Agricultural University. The top five authors are Todd C. Wehner (Wehner, TC), Jack E. Staub (Staub, JE), Yiqun Weng, R.L. Lower, and S. Tachibana; each published more than 24 articles. All keywords used for cucumber research in the horticulture category were separated into eight clusters for different research topics. Visualizations offer exploratory information regarding the current state in a scientific field or discipline as well as indicate possible developments in the future. This review could be a valuable guide for designing future studies.