Supplementary Light with Increased Blue Fraction Accelerates Emergence and Improves Development of the Inflorescence in Aechmea, Guzmania and Vriesea

In protected cultivation, increasing the light level via supplementary lighting (SL) is critical to improve external quality, especially in periods with low light availability. Despite wide applications, the effect of light quality remains understated. In this study, the effect of SL quality and nutrient solution electrical conductivity (EC) on growth and flowering of three bromeliad species was investigated. Treatments included solar light, and this supplemented with R90B10 [90% red (R) and 10% blue (B)], R80B20 (80% R and 20% B), and R70B30 (70% R and 30% B). These were combined with an EC of 1 and 2 dS m-l. Irrespective of the light treatment, the higher EC promoted growth, inflorescence emergence, and development in Aechmea fasciata (Lindl.) Baker, whereas adverse effects were noted in Guzmania and Vriesea. The higher EC-induced negative effect in Guzmania and Vriesea was slightly alleviated by SL. With few notable exceptions, SL exerted limited effects on photosynthetic functionality. Depending on the species, SL improved external quality traits. In all species, SL increased root and inflorescence weight and stimulated biomass allocation to generative organs. It also accelerated inflorescence emergence and promoted inflorescence development. In this way, the time to commercial development stage was considerably shortened. These effects were more prominent at R80B20 and R70B30. Under those conditions, for instance, inflorescence emergence occurred 3–5 weeks earlier than in the control, depending on the species. In conclusion, SL with increased B proportion leads to shorter production period owing to faster emergence and improved development of the inflorescence and is recommended for commercial use.

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Effects of ambient climate and three different warming treatments on fruit production in an alpine meadow community

10.32942/osf.io/zn3we ◽

2019 ◽

Author(s):

Juha Alatalo ◽

Annika Jägerbrand ◽

Junhu Dai ◽

Mohammad D. Mollazehi ◽

Abdel-Salam G. Abdel-Salam ◽

...

Keyword(s):

Climate Change ◽

Alpine Meadow ◽

Summer Precipitation ◽

Fruit Production ◽

Pulse Treatment ◽

The Press ◽

Negative Effect ◽

Deciduous Shrubs ◽

Evergreen Shrubs ◽

Production Period

Climate change is already having a major impact on alpine and arctic regions, and inter-annual variations in temperature are likely to increase. In a four-year study focusing on fruit production by an alpine plant community in northern Sweden, we applied three different warming regimes over the years. Treatments consisted of (a) a static level of warming with open-top chambers (OTC), (b) press warming, a yearly stepwise increases in warming, and (c) pulse warming, a single-year pulse event of higher warming. We analysed the relationship between fruit production and monthly temperatures during the budding period, fruiting period, and whole fruit production period, and the effect of winter and summer precipitation on fruit production. We found a significant effect of both year and treatment on total fruit production (highest in the press and lowest in the pulse treatment) and in the evergreen shrubs Cassiope tetragona (highest fruit production in press and lowest in pulse treatment) and Dryas octopetala (highest fruit production in press and pulse treatments), with large variations between treatments and years. Year, but not treatment, had a significant effect on deciduous shrubs and graminoids, both of which increased fruit production over the years, while forbs were negatively affected by the press treatment, but not year. Fruit production was influenced by ambient temperature during previous-year budding period, current-year fruiting period and the whole fruit production period. Minimum and average temperature were more important than maximum temperature. In general, increased precipitation was negatively correlated with fruit production. Summer precipitation decreased fruit production of D. octopetala, graminoids, deciduous shrubs, and total fruit production. Winter precipitation had a negative effect on fruit production of C. tetragona, evergreen shrubs, and total fruit production, while graminoids were positive affected. Similarly, the combined precipitation (winter and summer) had negative effect on fruit production of D. octopetala, deciduous and evergreen shrubs, graminoids, and total fruit production. In contrast, fruit production of forbs was not affected by precipitation. These results indicate that the predicted increased climate variability and increase in precipitation due to climate change may affect plant reproductive output and long-term community dynamics in alpine meadow communities.

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A Study on Risk Assessment of the Commercial Development Stage of New Product in Manufacturing Enterprises

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.248.495 ◽

2012 ◽

Vol 248 ◽

pp. 495-498

Author(s):

Xiao Wei Liu ◽

Xu Yun Liu

Keyword(s):

Risk Assessment ◽

Product Development ◽

New Product Development ◽

Evaluation Method ◽

Comprehensive Evaluation ◽

New Product ◽

Fuzzy Comprehensive Evaluation ◽

Development Stage ◽

Commercial Development ◽

Manufacturing Enterprises

The new product development of manufacturing Enterprises is not only complicated, expensive and more difficult,but the risk is higher.There will be many uncertain factors.An enterprise carries on the risk assessment,analyzes conclusion and proposes counter measures on the commercial development stage of new product in manufacturing enterprises by analyzing the risk factors and building an effective risk assessment index system including 6 first-level indicators and 22 secondary indicators of the commercial development stage of new product,along with the weight factor table method and fuzzy comprehensive evaluation method,which will reduce the risk and improve success rate of new product development,thus providing a theoretical basis for enterprises to improve risk management capabilities.

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Light and Nutrient Effects on the Relative Biomass of Blue-Green Algae in Lake Phytoplankton

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-016 ◽

1986 ◽

Vol 43 (1) ◽

pp. 148-153 ◽

Cited By ~ 146

Author(s):

Val H. Smith

Keyword(s):

Green Algae ◽

Current Knowledge ◽

Light Availability ◽

Light Level ◽

Algal Community ◽

Regression Analyses ◽

Secchi Disc ◽

Blue Green Algae ◽

Nutrient Effects ◽

Using Data

The factors determining the relative biomass of blue-green algae during the growing season were studied using data from 22 lakes worldwide. Multiple linear regression analyses suggest that total nitrogen (TN), total phosphorus (TP), and light (as estimated from Secchi disc transparency and the depth of the mixed layer) interact to determine the relative biomass of planktonic blue-green algae. At a fixed TN: TP ratio, blue-green relative biomass increases as light availability decreases. At a fixed light level, blue-green relative biomass also increases as the TN: TP ratio decreases. Both effects are consistent with current knowledge of algal physiology, and with a recently proposed theoretical framework for algal community structure.

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The distribution of Vallisneria americana seeds and seedling light requirements in the Upper Mississippi River

Canadian Journal of Botany ◽

10.1139/b95-210 ◽

1995 ◽

Vol 73 (12) ◽

pp. 1966-1973 ◽

Cited By ~ 28

Author(s):

Anne Kimber ◽

Arnold G. van der Valk ◽

Carl E. Korschgen

Keyword(s):

Seed Germination ◽

Mississippi River ◽

Seedling Survival ◽

Light Availability ◽

Light Response ◽

Light Level ◽

Vallisneria Americana ◽

Upper Mississippi River ◽

Light Requirements ◽

Viable Seeds

Vallisneria americana declined in backwaters of the Upper Mississippi River, U.S.A., after a drought in 1988. To determine whether viable seeds of V. americana occurred in the seed bank of navigation pool 7, Lake Onalaska, the upper 5 cm of sediment was collected from 103 sites in May 1990. These sediment samples were kept in pots at a depth of 0.4, 0.8, and 1.2 m in an outdoor pond for 12 weeks. Vallisneria americana seeds germinated from sites throughout the lake, and some seedlings produced overwintering buds by the end of the study. Seeds, spores, or fragments of 12 other species of aquatic plants also germinated. Seed germination trials with fresh and stored seeds in both greenhouse and ponds in which light availability was reduced with shade cloths indicated that seed germination was insensitive to light level. To determine the light requirements for seedling survival and bud production, sediment from Lake Onalaska was incubated in ponds under neutral density shade screens reducing light to 2, 5, 9, and 25% of full sun. Seeds germinated under all shade treatments but survival was significantly higher in the 9 and 25% light treatments, and bud production was restricted to these light levels. Key words: aquatic macrophytes, seeds, germination, light response.

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Advances in Agriculture Robotics: A State-of-the-Art Review and Challenges Ahead

Robotics ◽

10.3390/robotics10020052 ◽

2021 ◽

Vol 10 (2) ◽

pp. 52

Author(s):

Luiz F. P. Oliveira ◽

António P. Moreira ◽

Manuel F. Silva

Keyword(s):

Computer Vision ◽

State Of The Art ◽

Research Work ◽

Development Stage ◽

Robotic Systems ◽

Future Research ◽

Yield Estimation ◽

Commercial Development ◽

Land Preparation ◽

Smart Agriculture

The constant advances in agricultural robotics aim to overcome the challenges imposed by population growth, accelerated urbanization, high competitiveness of high-quality products, environmental preservation and a lack of qualified labor. In this sense, this review paper surveys the main existing applications of agricultural robotic systems for the execution of land preparation before planting, sowing, planting, plant treatment, harvesting, yield estimation and phenotyping. In general, all robots were evaluated according to the following criteria: its locomotion system, what is the final application, if it has sensors, robotic arm and/or computer vision algorithm, what is its development stage and which country and continent they belong. After evaluating all similar characteristics, to expose the research trends, common pitfalls and the characteristics that hinder commercial development, and discover which countries are investing into Research and Development (R&D) in these technologies for the future, four major areas that need future research work for enhancing the state of the art in smart agriculture were highlighted: locomotion systems, sensors, computer vision algorithms and communication technologies. The results of this research suggest that the investment in agricultural robotic systems allows to achieve short—harvest monitoring—and long-term objectives—yield estimation.

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Increased Levels of Calcium in the Nutrient Solution Improves the Postharvest Life of Potted Roses

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.122.6.863 ◽

1997 ◽

Vol 122 (6) ◽

pp. 863-868 ◽

Cited By ~ 19

Author(s):

Kirsten Rasmussen Starkey ◽

Asger Roer Pedersen

Keyword(s):

Nutrient Solution ◽

Matter Content ◽

The Other ◽

Postharvest Quality ◽

Dry Matter Content ◽

Grey Mold ◽

Negative Effect ◽

Postharvest Life ◽

Production Period ◽

The Rose

Experiments were performed on miniature potted roses (Rosa) to investigate whether increasing the Ca concentration in the nutrient solution would increase the Ca concentration in the rose plant, resulting in better postharvest quality. The plants were watered during the whole production period with six different nutrient solutions with Ca at 1.1 to 4.4 mm and varying meq ratios between Ca and the cations. During the postharvest period, plant characteristics were recorded at days 0, 11, 14, 18, and 25. Increasing Ca in the nutrient solution significantly increased the Ca concentration of the plants. However, the NH4 level (2% to 5% vs. 22% to 25%) also influenced the Ca concentration of the plants. Leaves had the highest Ca concentration, which was more than twice the level in flowers and buds, stems and roots. There were no differences in dry matter content between treatments in roots or tops at marketing stage. At the start of the postharvest treatment (day 0), plants from the highest Ca treatment had significantly fewer flowers than those in all of the other treatments due to delayed development. The number of good flowers increased from days 0 to 14 irrespective of treatment, while a further increase to day 18 was observed in plants from the three highest Ca treatments (low NH4) due to a negative effect on flower longevity of low Ca and high NH4 in the three low-Ca treatments. By day 25, the number of good flowers had decreased markedly in all treatments, but plants from the second-highest Ca treatment had significantly more good flowers than plants from the other treatments. Flower wilting was due to infection by grey mold (Botrytis cinerea) and a physiological condition that caused wilting that began at the petal edges with a dark discoloration. Infection with grey mold was negatively correlated with Ca concentration in the flowers. The physiological wilting was seen earlier in plants from the treatments with high NH4 and is probably not related to Ca concentration in the flowers.

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Foliar-applied GA3 Advances Fruit Maturity and Allows Off-season Harvest of ‘Hass’ Avocado

HortScience ◽

10.21273/hortsci.42.2.257 ◽

2007 ◽

Vol 42 (2) ◽

pp. 257-261 ◽

Cited By ~ 1

Author(s):

Samuel Salazar-García ◽

Luis E. Cossio-Vargas ◽

Isidro J.L. González-Durán ◽

Carol J. Lovatt

Keyword(s):

Gibberellic Acid ◽

Foliar Application ◽

Fruit Size ◽

Inflorescence Development ◽

Avocado Fruit ◽

Negative Effect ◽

Effect On Yield ◽

Hass Avocado ◽

Vegetative And Reproductive Growth ◽

Prohexadione Calcium

Michoacán and Nayarit are, respectively, the largest and second largest avocado-producing states in Mexico. The main harvest of the ‘Hass’ avocado in both states is concentrated during November to December, which saturates the market and reduces the price of fruit and grower income. The goal of this research was to manipulate vegetative and reproductive growth of the ‘Hass’ avocado with properly timed foliar-applied plant bioregulators (PBRs) to shift the date of flowering and harvest to the period before or after the main harvest. Effects of canopy sprays of gibberellic acid (GA3) or prohexadione calcium (a gibberellic acid biosynthesis inhibitor) applied at different stages of tree phenology on inflorescence development, time of anthesis, date of legal maturity for harvest of ‘Hass’ avocado fruit, yield, and fruit size were quantified. No PBR treatment influenced the time of anthesis. A single or double foliar application of GA3 (50 mg·L−1) ≈4 months (July) before the expected date of main harvest (November) resulted in ‘Hass’ avocado fruit reaching legal maturity (mesocarp dry matter 21.5% or greater) 24.8 to 28.2 d earlier than those of untreated control trees with no negative effect on yield or fruit size.

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Competitive responses of seedlings and understory plants in longleaf pine woodlands: separating canopy influences above and below ground

Canadian Journal of Forest Research ◽

10.1139/x06-247 ◽

2007 ◽

Vol 37 (3) ◽

pp. 634-648 ◽

Cited By ~ 39

Author(s):

Stephen D. Pecot ◽

Robert J. Mitchell ◽

Brian J. Palik ◽

E. Barry Moser ◽

J. Kevin Hiers

Keyword(s):

Seedling Survival ◽

Longleaf Pine ◽

Light Availability ◽

Pinus Palustris ◽

Light Level ◽

Belowground Competition ◽

Understory Plants ◽

Pine Seedlings ◽

Single Tree Selection ◽

Below Ground

A trenching study was used to investigate above- and below-ground competition in a longleaf pine ( Pinus palustris P. Mill.) woodland. Trenched and nontrenched plots were replicated in the woodland matrix, at gap edges, and in gap centers representing a range of overstory stocking. One-half of each plot received a herbicide treatment to remove the understory. We monitored pine survival and growth, understory productivity, light level (gap fraction), and soil resources. The overstory facilitated pine seedling survival. Pine seedling growth was reduced as overstory stocking increased. Reduced growth of seedlings was also observed in gaps when the understory was left intact. Understory plants competed with seedlings by filling the root gaps that developed as a result of overstory disturbance. Hardwood growth increased in gaps, owing to decreased belowground competition with adult pines, while growth of herbaceous plants and pine seedlings increased with light availability. Large overstory gaps are not required to initiate regeneration in longleaf pine woodlands. Retaining overstory dispersed throughout the stand but variable in density, through single-tree selection approaches, may be an alternative to gap-based approaches. This approach would allow for the fuel continuity needed to sustain the frequent fire required to maintain the diversity characteristic of this type of woodland.

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Genome-wide transcript analysis of inflorescence development in wheat

Genome ◽

10.1139/gen-2018-0200 ◽

2019 ◽

Vol 62 (9) ◽

pp. 623-633

Author(s):

Dae Yeon Kim ◽

Min Jeong Hong ◽

Yong Weon Seo

Keyword(s):

Cell Division ◽

Developmental Stages ◽

Early Stage ◽

Meta Analysis ◽

Development Stage ◽

Yield Potential ◽

Regulation Mechanism ◽

Inflorescence Development ◽

Grain Number Per Spike ◽

Genechip Array

The process of inflorescence development is directly related to yield components that determine the final grain yield in most cereal crops. Here, microarray analysis was conducted for four different developmental stages of inflorescence to identify genes expressed specifically during inflorescence development. To select inflorescence-specific expressed genes, we conducted meta-analysis using 1245 Affymetrix GeneChip array sets obtained from various development stages, organs, and tissues of members of Poaceae. The early stage of inflorescence development was accompanied by a significant upregulation of a large number of cell differentiation genes, such as those associated with the cell cycle, cell division, DNA repair, and DNA synthesis. Moreover, key regulatory genes, including the MADS-box gene, KNOTTED-1-like homeobox genes, GROWTH-REGULATING FACTOR 1 gene, and the histone methyltransferase gene, were highly expressed in the early inflorescence development stage. In contrast, fewer genes were expressed in the later stage of inflorescence development, and played roles in hormone biosynthesis and meiosis-associated genes. Our work provides novel information regarding the gene regulatory network of cell division, key genes involved in the differentiation of inflorescence in wheat, and regulation mechanism of inflorescence development that are crucial stages for determining final grain number per spike and the yield potential of wheat.

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The effect of the shape of gaps on microenvironmental conditions and seedling recruitment in Molinietum caeruleae meadows

Acta Agrobotanica ◽

10.5586/aa.2015.021 ◽

2015 ◽

Vol 32 (2) ◽

pp. 143-151 ◽

Cited By ~ 1

Author(s):

Kinga Kostrakiewicz-Gierałt

Keyword(s):

Secondary Succession ◽

Seedling Recruitment ◽

Light Availability ◽

Life Forms ◽

Plant Canopy ◽

Natural Habitats ◽

Young Tree ◽

Tree Communities ◽

Negative Effect ◽

Tussock Grasses

Cessation of the management of semi-natural habitats such as grasslands and meadows contributes to secondary succession and encroachment of native and alien tall-growing perennials, large tussock grasses, shrubs, and trees. Thus, the formation of gaps in the plant canopy and litter, enabling seedling recruitment, appears to be a very effective method for the restoration of several plant communities. The main objective of the research was to assess the effect of the shape of openings on microenvironmental conditions and seedling recruitment in <em>Molinietum caeruleae</em> patches in various habitat conditions. In all study patches, circular and linear openings, comparable in area, were randomly created through the removal of plant canopy and litter layer. The circular gaps presented greater light availability and lower soil humidity than linear openings, while soil temperature within differently shaped openings was similar. Regardless of differences in microenvironmental conditions, the total number of seedlings in differently shaped gaps did not vary considerably. Three plant categories were found: (i) those recruited mostly in circular openings, (ii) those recruited mostly in linear gaps, (iii) those colonizing circular and linear gaps similarly. The colonizers of circular gaps represented various synecological groups (ruderal, grasslands and meadows, young tree communities) and diverse life forms (therophytes, hemicryptophytes, chamaephytes, phanerophytes), while the colonizers of linear gaps were meadow and grassland hemicryptophytes. The formation of linear openings contributes to increases in the abundance of meadow taxa, while the creation of circular openings may have a negative effect, contributing to the promotion of the secondary succession process.

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