scholarly journals Bell Pepper (Capsicum annum L.) Crop as Affected by Shade Level: Microenvironment, Plant Growth, Leaf Gas Exchange, and Leaf Mineral Nutrient Concentration

HortScience ◽  
2013 ◽  
Vol 48 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Juan Carlos Díaz-Pérez
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Soil Water ◽  
Leaf Area ◽  
Leaf Gas Exchange ◽  
Bell Pepper ◽  
Mineral Nutrient ◽  
Specific Leaf Weight ◽  
Leaf Weight ◽  
Leaf Transpiration

Use of shading nets helps ameliorate heat stress of vegetable crops. This study evaluated the effects of shade level on microenvironment, plant growth, leaf gas exchange, and mineral nutrient content of field-grown bell pepper crop. Bell pepper cultivars Camelot, Lafayette, Sirius, and Stiletto were grown at 0%, 30%, 47%, 62%, and 80% shade levels. Photosynthetically active radiation and air, leaf, and root zone temperatures decreased as shade level increased. Despite having increased plant leaf area, there was increased soil water content with increased shade level, indicating reduced soil water use. With increased shade level, the total plant leaf area, individual leaf area, and individual leaf weight increased, whereas leaf number per plant and specific leaf weight decreased. In contrast to non-normalized chlorophyll index (CI) values, CI normalized by specific leaf weight were related to leaf nitrogen (N) and increased with increased shade level. Net photosynthesis and stomatal conductance (gS) decreased and leaf transpiration increased with increased shade level, particularly above 47% shade level. Leaf concentrations of N, potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), sulfur (S), aluminum (Al), and boron (B) increased with increased shade level. Relatively few differences in plant growth, leaf gas exchange, and leaf mineral nutrient concentrations were observed among cultivars. In conclusion, morphological changes such as taller plants and thinner and larger leaves likely enhanced light capture under shaded conditions compared with unshaded plants. High shade levels reduced leaf temperature and excessive leaf transpiration but resulted in reduced leaf photosynthesis. Thus, moderate shade levels (30% and 47%) were the most favorable for bell pepper plant growth and function.

scholarly journals Bell Pepper (Capsicum annum L.) Grown on Plastic Film Mulches: Effects on Crop Microenvironment, Physiological Attributes, and Fruit Yield

HortScience ◽  
2010 ◽  
Vol 45 (8) ◽  
pp. 1196-1204 ◽  
Author(s):  
Juan Carlos Díaz-Pérez
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Soil Water ◽  
Water Status ◽  
Mineral Nutrients ◽  
Fruit Yield ◽  
Bell Pepper ◽  
Plastic Film ◽  
Plastic Mulch ◽  
Soil Water Status

Plastic mulches are widely used for the production of vegetables. There are numerous studies on the use of plastic mulches for peppers, although relatively few have focused on the microenvironmental and physiological impacts of plastic mulches on bell pepper. The objectives were to determine the effects of plastic film mulches on root zone temperature (RZT), soil water status, incidence of thrips and Tomato spotted wilt (TSW), plant growth, gas exchange, accumulation of mineral nutrients, and fruit yield in bell pepper. The study was conducted in Tifton, GA, in the Fall of 2002 and the Spring of 2003 using eight colored plastic mulches. Plastic mulch color influenced the microenvironmental, physiological, and yield responses of bell pepper plants. Plastic film mulches differed in their soil-warming ability with RZTs in both spring and fall being highest in black mulches and lowest in silver mulches. The percentage of photosynthetically active radiation (PAR) reflected from the mulches was highest in silver mulches and lowest in black mulches. The mean RZT under the plastic mulch decreased with increasing percentages of reflected PAR. The number of thrips per flower and the incidence of TSW in mature plants were not significantly different among plastic mulch treatments. The number of thrips per flower had no relationship with the percentage of reflected PAR or with RZT. Plastic mulch treatments had no significant effect on soil water status. Neither soil water content nor soil water potential had a relationship with RZT. In the fall season, during the first 28 days after transplanting, plant growth attributes were among the highest in silver mulches and the lowest in black mulches. Gas exchange and accumulation of mineral nutrients in the leaves and the fruit were not significantly affected by plastic mulches. Both marketable and total yields were higher on silver mulches and lowest on black mulch in the fall, whereas they were in general higher on silver with a black strip mulch and lowest on white and silver1 mulches in the spring. The reduced plant growth and fruit yields in black mulches during the fall were probably the result of the increased RZTs, and thus higher heat accumulation, that resulted in higher plant heat stress conditions compared with silver and white mulches. Fruit yield decreased with mean seasonal RZTs above 27.5 °C. The optimal range of RZT for bell pepper fruit yield was computed to be 25 to 27.5 °C or less.

Reexamining the empirical relation between plant growth and leaf photosynthesis

2006 ◽  
Vol 33 (5) ◽  
pp. 421 ◽  
Author(s):  
Eric L. Kruger ◽  
John C. Volin
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Leaf Area ◽  
Leaf Gas Exchange ◽  
Empirical Relation ◽  
Leaf Photosynthesis ◽  
Unit Leaf Area ◽  
Leaf Mass ◽  
Unit Leaf ◽  
Growth Variation

Technological advances during the past several decades have greatly enhanced our ability to measure leaf photosynthesis virtually anywhere and under any condition. Associated with the resulting proliferation of gas-exchange data is a lingering uncertainty regarding the importance of such measurements when it comes to explaining intrinsic causes of plant growth variation. Accordingly, in this paper we rely on a compilation of data to address the following questions: from both statistical and mechanistic standpoints, how closely does plant growth correlate with measures of leaf photosynthesis? Moreover, in this context, does the importance of leaf photosynthesis as an explanatory variable differ among growth light environments? Across a wide array of species and environments, relative growth rate (RGR) was positively correlated with daily integrals of photosynthesis expressed per unit leaf area (Aarea), leaf mass (Amass), and plant mass (Aplant). The amount of RGR variation explained by these relationships increased from 36% for the former to 93% for the latter. Notably, there was close agreement between observed RGR and that estimated from Aplant after adjustment for theoretical costs of tissue construction. Overall, based on an analysis of growth response coefficients (GRCs), gross assimilation rate (GAR), a photosynthesis-based estimate of biomass gain per unit leaf area, explained about as much growth variation as did leaf mass ratio (LMR) and specific leaf area (SLA). Further analysis of GRCs indicated that the importance of GAR in explaining growth variation increased with increasing light intensity. Clearly, when considered in combination with other key determinants, appropriate measures of leaf gas exchange effectively capture the fundamental role of leaf photosynthesis in plant growth variation.

scholarly journals Bell Pepper (Capsicum annum L.) under Colored Shade Nets: Plant Growth and Physiological Responses

HortScience ◽  
2019 ◽  
Vol 54 (10) ◽  
pp. 1795-1801 ◽  
Author(s):  
Juan Carlos Díaz-Pérez ◽  
Kelly St. John
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Antioxidant Capacity ◽  
Root Zone ◽  
Leaf Gas Exchange ◽  
Leaf Temperature ◽  
Stem Diameter ◽  
Bell Pepper ◽  
Fresh Weight ◽  
Total Carotenoids

Use of colored shade nets has shown benefits in bell pepper and other horticultural crops. There is still, however, limited information on plant growth and physiology of bell pepper crop grown under colored shade nets. The objective was to determine the effects of colored shade nets on plant growth, leaf gas exchange, and leaf pigments of field-grown bell pepper. Experimental design was a randomized complete block with four replications and five shade treatments (black, red, silver, and white nets, and an uncovered control). Mean and maximal air temperature and midday root zone temperature (RZT) were highest in the unshaded treatment. Differences in air temperatures between shade net treatments were smaller compared with the differences in RZT between treatments. Plant fresh weight and stem diameter were reduced in the unshaded treatment, and there were no plant fresh weight and stem diameter differences among shade nets. The incidence of Phytophthora blight (caused by Phytophthora capsici) was greatest in the unshaded treatment. Leaf stomatal conductance (gS) and photosystem II efficiency were reduced and leaf temperature increased in unshaded conditions. Leaf net photosynthesis, gS, internal CO2, and PSII efficiency decreased with increasing leaf temperature. Differences in leaf temperature among shade net treatments were because of differences in solar radiation captured by leaves. Leaf total carotenoids were lowest in unshaded conditions and there were no differences in total carotenoids among the shade nets. Chlorophyll a concentration and chlorophyll a/b ratio was lowest in unshaded conditions. Leaf total phenols, flavonoids, and cupric reducing antioxidant capacity (CUPRAC) values were highest in red net and in unshaded conditions. Trolox equivalent antioxidant capacity (TEAC) values were highest in red net and lowest in silver net. In conclusion, compared with unshaded conditions, shade nets resulted in improved bell pepper plant growth and leaf gas exchange. These responses were due primarily to the reduced leaf and root zone temperatures under shaded conditions, regardless of the color of shade net. The differences in plant growth and function due to color of shade net were inconsistent or minor for most of the plant variables measured.

scholarly journals Mycorrhizal roles in plant growth, gas exchange, root morphology, and nutrient uptake of walnuts

2020 ◽  
Vol 66 (No. 6) ◽  
pp. 295-302 ◽  
Author(s):  
Guang-Ming Huang ◽  
Ying-Ning Zou ◽  
Qiang-Sheng Wu ◽  
Yong-Jie Xu ◽  
Kamil Kuča
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Root Morphology ◽  
Mycorrhizal Fungi ◽  
Leaf Gas Exchange ◽  
Juglans Regia ◽  
Mycorrhizal Fungus ◽  
Mineral Nutrient ◽  
Positive Role ◽  
Nutrient Contents

Walnut, an important oil fruit tree, is dependent on arbuscular mycorrhizas, while mycorrhizal roles and efficient mycorrhizal fungus in walnuts are unknown. This study was conducted to evaluate the effect of five arbuscular mycorrhizal fungi (AMF) species, including Acaulospora scrobiculata, Diversispora spurca, Glomus etunicatum, G. mosseae, and G. versiforme on plant growth, leaf gas exchange, root morphology, and root nutrient contents of walnut (Juglans regia L. Liaohe 1) seedlings. Three months of AMF inoculations later, root mycorrhizal colonisation achieved 47.0% to 76.4%. AMF treatments increased plant growth performance, dependent on AMF species. AMF-inoculated plants with D. spurca, G. etunicatum, and G. mosseae showed higher root length, projected area, surface area, and volume than non-AMF plants. Except for G. versiforme, the other four AMF treatments almost significantly increased leaf photosynthesis rate, transpiration rate, and stomatal conductivity, while reduced intercellular CO<sub>2</sub> concentrations and leaf temperature. AMF affected root nutrient contents, dependent on AMF and mineral nutrient species. These results, thereby, concluded that AMF had a positive role in walnuts, dependent on AMF species, and D. spurca was the best mycorrhizal fungus for walnut. Such results provide the potential possibility of a developing consortium of AMF in walnut cultivation management.

Seasonal responses of leaf gas exchange to elevated carbon dioxide in Populusgrandidentata

1992 ◽  
Vol 22 (9) ◽  
pp. 1320-1325 ◽  
Author(s):  
Peter S. Curtis ◽  
James A. Teeri
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Partial Pressure ◽  
Leaf Area ◽  
Leaf Gas Exchange ◽  
Exposure Period ◽  
Initial Slope ◽  
Carbon Gain ◽  
Late Season ◽  
Leaf Weight

Rising atmospheric carbon dioxide concentrations may have important consequences for forest ecosystems. We studied above- and below-ground growth and leaf gas exchange responses of Populusgrandidentata Michx. to elevated CO2 under natural forest conditions over the course of a growing season. Recently emerged P. grandidentata seedlings were grown in native, nutrient-poor soils at ambient and twice ambient (707 μbar (1 bar = 100 kPa)) CO2 partial pressure for 70 days in open-top chambers in northern lower Michigan. Total leaf area and shoot and root dry weight all increased in high CO2 grown plants. Photosynthetic light and CO2 response characteristics were measured 28, 45, and 68 days after exposure to elevated CO2. In ambient grown plants, light saturated assimilation rates increased from day 28 to day 45 and then declined at day 68 (15 September). This late-season decline, typical of senescing Populus leaves, was due both to a decrease in the initial slope of the net CO2 assimilation versus intercellular CO2 partial pressure relationship and to decreased CO2 saturated assimilation rates. Specific leaf nitrogen (mg N•(cm2 leaf area)−1) did not change during this period, although leaf carbon content and leaf weight (mg•cm−2) both increased. In ambient grown plants stomatal conductance also declined at day 68. In contrast, plants grown at elevated CO2 showed no late-season decline in photosynthetic capacity or changes in leaf weight, suggesting a delay in senescence with long-term exposure to high CO2. High CO2 grown plants also maintained photosynthetic sensitivity to increasing Ci throughout the exposure period, while ambient CO2 grown plants were insensitive to Ci above 400 μbar on day 68. These results indicate the potential for direct CO2 fertilization of P. grandidentata in the field and provide evidence for a new mechanism by which elevated atmospheric CO2 could influence seasonal carbon gain.

Growth and leaf gas exchange in Populus euphratica across soil water and salinity gradients

2013 ◽  
Vol 51 (3) ◽  
pp. 321-329 ◽  
Author(s):  
J. Y. Li ◽  
C. Y. Zhao ◽  
J. Li ◽  
Y. Y. Yan ◽  
B. Yu ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Soil Water ◽  
Leaf Gas Exchange ◽  
Populus Euphratica ◽  
Salinity Gradients

scholarly journals Does insect herbivory suppress ecosystem productivity? Evidence from a temperate woodland

2021 ◽  
Author(s):  
Kristiina Visakorpi ◽  
Sofia Gripenberg ◽  
Yadvinder Malhi ◽  
Terhi Riutta
Keyword(s):  
Gas Exchange ◽  
Leaf Area ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Leaf Gas Exchange ◽  
Insect Herbivory ◽  
Ecosystem Productivity ◽  
Area Loss ◽  
Leaf Area Loss ◽  
The Relationship

AbstractOur current understanding of the relationship between insect herbivory and ecosystem productivity is limited. Previous studies have typically quantified only leaf area loss, or have been conducted during outbreak years. These set-ups often ignore the physiological changes taking place in the remaining plant tissue after insect attack, or may not represent typical, non-outbreak herbivore densities. Here, we estimate the amount of carbon lost to insect herbivory in a temperate deciduous woodland both through leaf area loss and, notably, through changes in leaf gas exchange in non-consumed leaves under non-outbreak densities of insects. We calculate how net primary productivity changes with decreasing and increasing levels of herbivory, and estimate what proportion of the carbon involved in the leaf area loss is transferred further in the food web. We estimate that the net primary productivity of an oak stand under ambient levels of herbivory is 54 - 69% lower than that of a completely intact stand. The effect of herbivory quantified only as leaf area loss (0.1 Mg C ha−1 yr−1) is considerably smaller than when the effects of herbivory on leaf physiology are included (8.5 Mg C ha−1 yr−1). We propose that the effect of herbivory on primary productivity is non-linear and mainly determined by changes in leaf gas exchange. We call for replicated studies in other systems to validate the relationship between insect herbivory and ecosystem productivity described here.

scholarly journals Growth of sweet pepper plants submitted to water tensions in soil and potassium silicate doses

2019 ◽  
Vol 37 (1) ◽  
pp. 82-88
Author(s):  
Alexandre Igor A Pereira ◽  
João de Jesus Guimarães ◽  
João Victor Costa ◽  
Fernando S de Cantuário ◽  
Leandro C Salomão ◽  
...  
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Soil Water ◽  
Leaf Area ◽  
Capsicum Annuum ◽  
Sweet Pepper ◽  
Potassium Silicate ◽  
Growth Responses ◽  
Resistance Inducers ◽  
Pepper Plants

ABSTRACT Water stress compromises plant growth. Resistance inducers, such as potassium silicate (K2SiO3), can reduce negative effects of this stress on Solanaceae, Capsicum annuum. Plant height, stem diameter and leaf area may indicate the efficiency of potassium silicate foliarsprayagainst water stress. The aim of this study was to evaluate the growth of sweet pepper plants under water stress and K2SiO3 doses. The experiment was conducted in randomized blocks in a split-plot scheme in space. The treatments consisted of four soil water stresses: 15 kPa (field capacity), 25 (intermediate value), 35 and 45 kPa (water stress) and three doses of potassium silicate (0, 0.4 and 0.8 L 100 L-1 water), acting as resistance inducers to water stress. The resistance inducer maintained greater heights of the sweet pepper plants, under water stress (35 and 45 kPa) at the initial stage [(20 days after transplanting (DAT)]. Smaller plant diameters were observed at 80 and 100 DAT at 35 and 45 kPa. Sprays using K2SiO3 maintained sweet pepper leaf area with higher values, even under stress condition. The soil water tension from 35 kPa limited, in general, the plant growth. Growth responses in Capsicum annuum to K2SiO3, via foliar spraying, varied according to plant age, as well as the growth parameter considered in this experiment.

VARIABILITY IN FORAGE AND SEED PRODUCTION AND SEEDLING GROWTH IN ASTRAGALUS CICER

1976 ◽  
Vol 56 (3) ◽  
pp. 487-491 ◽  
Author(s):  
S. SMOLIAK ◽  
A. JOHNSTON
Keyword(s):  
Leaf Area ◽  
Seed Weight ◽  
Germination Percentage ◽  
Forage Yield ◽  
Seedling Vigor ◽  
Specific Leaf Weight ◽  
Leaf Weight ◽  
Astragalus Cicer ◽  
Seed Yields ◽  
Seedling Leaf

Forage and seed yield, percentage seed germination, speed of germination index, and 1,000-seed weight were determined for a population of 170 plants selected from Oxley cicer milkvetch (Astragalus cicer L.). Seedlings from open-pollinated seed from the selected plants were measured for leaf weight and leaf area, and specific leaf weight was calculated. Most of the characters studied were asymmetrical in distribution. The correlation coefficient between forage and seed yields of mature plants was positive and highly significant. Seedling leaf weight was positively and closely related to seedling leaf area, but seedling leaf area was a more reliable indicator of photosynthetic efficiency. The variability in the characters studied in the selected population suggests that further improvement in forage yield, germination percentage, speed of germination, and seedling vigor may be obtained through a breeding program.

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