scholarly journals Effect of Extended Photoperiod with a Fixed Mixture of Light Wavelengths on Tomato Seedlings

HortScience ◽  
2020 ◽  
Vol 55 (11) ◽  
pp. 1832-1839
Author(s):  
Humberto Aguirre-Becerra ◽  
Juan Fernando García-Trejo ◽  
Cristina Vázquez-Hernández ◽  
Aurora Mariana Alvarado ◽  
Ana Angélica Feregrino-Pérez ◽  
...  
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Negative Impact ◽  
Biomass Accumulation ◽  
Dry Weight ◽  
Artificial Light ◽  
Health Index ◽  
Ultraviolet A ◽  
Tomato Seedlings ◽  
Leaf Dry Weight

Light is an abiotic factor, and its quality, quantity, and photoperiod can be modulated to work as eustress inductors to regulate plant processes. It is known that red (R), blue (B), far-red (FR), and ultraviolet-A wavelengths can promote photomorphogenesis and secondary metabolite production in plants. Several ratios of R:B and the addition of end of-day FR, separately, have beneficial effects on plant development, whereas adding ultraviolet-A enhances the production of secondary metabolites such as phenols. However, the effects of extended photoperiods with a mixture of these four wavelengths and extra end-of-day FR have not been evaluated for plants of commercial interest. The objective of this study was to determine the effects on tomato seedlings (‘Saladette’, CORDOBA F1) of different overnight photoperiods using a fixed combination of R (625 nm), B (460 nm), FR (720 nm), and ultraviolet-A (410 nm). We expected increases in the production of specialized metabolites and the generation of beneficial changes in the seedling biomass and morphology. Four treatments involving overnight artificial light provided by a light-emitting diode (LED) module were established: TC (control), 0 h; T1, 4 hours; T2, 8 hours; and T3, 12 hours. All treatments were subjected to a 12-hour natural photoperiod and 12 hours of overnight artificial light. The experiment lasted 4 weeks, and plants were sampled every week for physical and phytochemical measurements. In general, seedlings subjected to 4-hour and 8-hour treatments presented better results than those subjected to the control and 12-hour overnight photoperiod treatments. Seedlings subjected to treatments with an 8-hour overnight photoperiod presented large accumulation of biomass in the stem rather than in the leaves because they had large stem dry weight, stem weight, and elongation and higher first, second, and third internode lengths; however, they had lower leaf area, leaf dry weight, and health index. Seedlings subjected to treatment with a 4-hour overnight photoperiod were visually bigger, with large leaf expansion, total length, stem weight, total weight, and specific leaf area; however, this treatment had a negative impact on the biomass accumulation, with lower leaf weight, stem dry weight, and health index. The 12-hour treatment had a negative impact on the leaf area, and thus the specific leaf area, of seedlings; however, the biomass accumulation was large, with higher leaf dry weight, total dry matter, and specific leaf area, but no difference in stem dry weight compared with the control. At the end of the experiment, the total phenolic content increased in all treatments compared with the control, but the flavonoid content decreased. Moreover, the antioxidant capacity was higher for T2 during the last 2 weeks of the experiment. Results are discussed according to the possibilities of using this light strategy for seedling production.

Recruitment and life-history traits of sparse plant species in subalpine grasslands

2003 ◽  
Vol 81 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Gunnar Austrheim ◽  
Ove Eriksson
Keyword(s):  
Leaf Area ◽  
Negative Correlation ◽  
Specific Leaf Area ◽  
Seedling Recruitment ◽  
Plant Traits ◽  
Dry Weight ◽  
Community Diversity ◽  
Safe Sites ◽  
Subalpine Grasslands ◽  
Leaf Dry Weight

Recruitment is critical for the maintenance of plant populations and community diversity, but sexual regeneration is considered to be infrequent in climatically harsh habitats such as subalpine grasslands. This study examines the importance of regeneration through seed for 16 sparse herb species, and we asked whether their populations are limited by safe sites or the availability of seeds. Seedling recruitment and winter survival were recorded after sowing in an experimental split-plot design in (i) pasture grazed by livestock, and (ii) exclosed grassland cultivated for annual mowing. In addition we examined the effect of disturbance and local seedbank recruitment. All species were able to recruit and survive the first winter in at least some of the experimental plots, although none were initially present. Recruitment mainly occurred in disturbed plots, and disturbed pasture plots had a significantly higher recruitment than disturbed exclosures for all species except Silene dioica. We further examined whether specific plant traits were related to variation in recruitment. Lower recruitment in the disturbed exclosure was associated with higher specific leaf area, leaf dry weight, and seed number. In contrast, seeds sown in disturbed pasture recruited more independently of species traits. The exception was a negative correlation between recruitment and leaf dry weight, and an unexpected negative correlation with seed weight. We suggest that recruitment differences among habitats mainly reflect lower humidity in the exclosure. Consequently, small stature plants with small specific leaf area should have the highest recruiting probability when exposed to drought. The almost exclusive recruitment on disturbed plots indicates a strong competitive effect on the target species in vegetated plots, and suggests that safe sites for regeneration through seed are rare in subalpine grasslands.Key words: colonization, herbs, plant abundance and distribution, disturbance, pastures, cultivated exclosures, sowing experiment.

scholarly journals Growth Analysis of Wheat Using Machine Vision: Opportunities and Challenges

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6501
Author(s):  
Mohammad Ajlouni ◽  
Audrey Kruse ◽  
Jorge A. Condori-Apfata ◽  
Maria Valderrama Valencia ◽  
Chris Hoagland ◽  
...  
Keyword(s):  
Growth Rate ◽  
Machine Vision ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Growth Analysis ◽  
Growth Parameters ◽  
Dry Weight ◽  
Projected Area ◽  
Relative Growth ◽  
Leaf Dry Weight

Crop growth analysis is used for the assessment of crop yield potential and stress tolerance. Capturing continuous plant growth has been a goal since the early 20th century; however, this requires a large number of replicates and multiple destructive measurements. The use of machine vision techniques holds promise as a fast, reliable, and non-destructive method to analyze crop growth based on surrogates for plant traits and growth parameters. We used machine vision to infer plant size along with destructive measurements at multiple time points to analyze growth parameters of spring wheat genotypes. We measured side-projected area by machine vision and RGB imaging. Three traits, i.e., biomass (BIO), leaf dry weight (LDW), and leaf area (LA), were measured using low-throughput techniques. However, RGB imaging was used to produce side projected area (SPA) as the high throughput trait. Significant effects of time point and genotype on BIO, LDW, LA, and SPA were observed. SPA was a robust predictor of leaf area, leaf dry weight, and biomass. Relative growth rate estimated using SPA was a robust predictor of the relative growth rate measured using biomass and leaf dry weight. Large numbers of entries can be assessed by this method for genetic mapping projects to produce a continuous growth curve with fewer replicates.

scholarly journals RESPONSE OF GAMAL (Gliricidia sepium) AND INDIGOFERA (Indigofera zollingeriana) FORAGE ON APPLICATION OF ANORGANIC AND ORGANIC FERTILIZER

Pastura ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 33
Author(s):  
Roni N.G.K. ◽  
S.A. Lindawati
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Plant Species ◽  
Organic Fertilizer ◽  
Dry Weight ◽  
Stem Diameter ◽  
Inorganic Fertilizer ◽  
Organic Fertilizers ◽  
Total Dry Weight ◽  
Leaf Dry Weight

The productivity of forage depends on the availability of nutrients in the soil where it is grown, so fertilization to replace harvested produce is absolutely necessary. This study aims to study the response of gamal and indigofera forage on application of inorganic and organic fertilizers. Research using a completely randomized design factorial pattern of two factors, the first factor is the type of plant (G = Gamal; I = Indigofera) and the second factor is the type of fertilizer (T = without Fertilizer; A = Inorganic fertilizer NPK; K = commercial organic fertilizer; O = conventional organic fertilizer; B = bioorganic fertilizer), repeated 4 times so that it consists of 40 experimental units. The variables observed were plant height, number of leaves, stem diameter, leaf dry weight, stem dry weight, total dry weight of leaves, ratio of dry weight of leaves/stems and leaf area per pot. The results showed that there was no interaction between plant species and types of fertilizer in influencing the response of gamal and indigofera plants. Plant species have a significant effect on stem diameter, while fertilizer types have a significant effect on plant height, leaf dry weight, total dry weight of leaves and leaf area per pot. Based on the results of the study it can be concluded that the response of gamal plants is similar to indigofera, all types of fertilizers can improve the response of plants and organic fertilizers produce the same crop response with inorganic fertilizers. Keywords: gamal, indigofera, inorganic fertilizer, organic fertilizer

scholarly journals Fitness Cost of Imazamox Resistance in Wild Poinsettia (Euphorbia heterophylla L.)

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1859
Author(s):  
Saeid Hassanpour-bourkheili ◽  
Mahtab Heravi ◽  
Javid Gherekhloo ◽  
Ricardo Alcántara-de la Cruz ◽  
Rafael De Prado
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Dry Weight ◽  
Area Ratio ◽  
Fitness Cost ◽  
Seed Plant ◽  
Growth Indices ◽  
Relative Growth ◽  
Net Assimilation

Wild poinsettia (Euphorbia heterophylla L.) is a difficult-to-control weed in soybean production in Brazil that has developed resistance to herbicides, including acetolactate synthase inhibitors. We investigated the potential fitness cost associated to the Ser-653-Asn mutation that confers imazamox resistance in this weed. Plant height, leaf and stem dry weight, leaf area and seed production per plant as well as the growth indices of specific leaf area, leaf area ratio, relative growth rate and net assimilation in F2 homozygous resistant (R) and susceptible (S) wild poinsettia progenies were pairwise compared. S plants were superior in most of the traits studied. Plant heights for S and R biotypes, recorded at 95 days after planting (DAP), were 137 and 120 cm, respectively. Leaf areas were 742 and 1048 cm2 in the R and S biotypes, respectively. The dry weights of leaves and stems in the S plants were 30 and 35%, respectively, higher than in the R plants. In both biotypes, the leaves had a greater share in dry weight at early development stages, but from 50 DAP, the stem became the main contributor to the dry weight of the shoots. The R biotype produced 110 ± 4 seed plant−1, i.e., 12 ± 3% less seeds per plant than that of the S one (125 ± 7 seed plant−1). The growth indices leaf area ratio and specific leaf area were generally higher in the S biotype or similar between both biotypes; while the relative growth rate and net assimilation rate were punctually superior in the R biotype. These results demonstrate that the Ser-653-Asn mutation imposed a fitness cost in imazamox R wild poinsettia.

An appropriate physiological control for environmental temperature studies: comparative growth kinetics of winter rye

1984 ◽  
Vol 62 (5) ◽  
pp. 1062-1068 ◽  
Author(s):  
M. Krol ◽  
M. Griffith ◽  
N. P. A. Huner
Keyword(s):  
Low Temperature ◽  
Leaf Area ◽  
Growth Response ◽  
Dry Weight ◽  
Maximum Growth ◽  
Cold Hardening ◽  
Lag Phase ◽  
Winter Rye ◽  
Kinetics Of ◽  
Leaf Dry Weight

The accurate interpretation of physiological and biochemical alterations observed in plants grown under contrasting environmental conditions requires knowledge of their relative physiological ages. For this purpose, we compared the growth kinetics of winter rye (Secale cereale L. cv. Puma) at nonhardening and cold-hardening temperatures. Growth at nonhardening temperatures was characterized by a 10-day lag phase with the attainment of maximum growth after about 28 days. Growth at cold-hardening temperatures resulted in an extension of the lag phase to about 21 days with maximum growth being attained after 56 days. The calculated growth coefficient at cold-hardening temperatures was 35–40% of that at nonhardening temperatures. This relationship was consistent with growth parameters such as leaf dry weight, fresh weight, and area, but not with plant height. Although total leaf dry weight and total number of leaves per plant did not differ between nonhardened and cold-hardened plants at maximum growth, total leaf area per plant and stretched plant height was 3- to 4-times greater in nonhardened than in cold-hardened plants. This resulted in a fourfold increase in leaf dry weight per leaf area during growth at low temperature in contrast to the maintenance of a constant ratio during growth at nonhardening conditions. The increase in this ratio during low temperature growth was, in part, accounted for by a decrease in water content and an increase in cytoplasmic content. These results were confirmed by the investigation of growth on an individual leaf basis. However, the growth response of leaves 1 and 2 differed from that of leaves 3 and 4 when the leaf dry weight: leaf area ratio was measured as a function of time at cold-hardening temperatures. This indicates that the stage of leaf development influences its growth response to an altered environment. The results of the development of leaf freezing tolerance indicated that maximum vegetative growth appeared to coincide with maximum freezing tolerance of leaves from cold-hardened plants (−22 °C) but not of leaves from unhardened plants (−11 °C).

Observations of the Photosynthetic Physiology of Tree Species within the C3 Monocotyledon Genus Pandanus, and Comparison with Dicotyledon C3 Tree Species

1998 ◽  
Vol 46 (1) ◽  
pp. 103 ◽  
Author(s):  
Catherine E. Lovelock
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Tree Species ◽  
Dark Respiration ◽  
Dry Weight ◽  
Weight Basis ◽  
Growth And Survival ◽  
Respiration Rates ◽  
Leaf Dark Respiration ◽  
Resource Levels

Photosynthetic characteristics of tree species from the tropical C3 monocotyledon genus Pandanus were compared with C3 dicotyledon species growing in similar environments. The Pandanus species had similar maximum photosynthetic rates (Amax) to dicotyledon tree species in leaves from both sun and shaded environments when Amax was expressed on an area basis. Because of the low specific leaf area of the schlerophyllous leaves of the Pandanus compared to the dicotyledon species, the similarity in Amax was no longer evident when Amax was expressed on a dry-weight basis. Leaf dark respiration rates of the Pandanus on a leaf area and weight basis were generally lower than the shade-intolerant dicotyledons and similar to the shade-tolerant dicotyledon species. Low dark respiration rates and low specific leaf area of the Pandanus may be important characteristics for growth and survival in environments where resource levels are low and the likelihood of tissue damage is high.

scholarly journals Effect of Nitrogen Fertilizer and Plant Spacing on Vegetative Growth of Sugar Beet (Beta vulgaris)

2021 ◽  
Vol 4 (1) ◽  
pp. 6-13
Author(s):  
Baha Eldin. M. Idris ◽  
Wael. A. Marajan ◽  
Abubaker Haroun Mohamed Adam
Keyword(s):  
Sugar Beet ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Nitrogen Fertilizer ◽  
Dry Weight ◽  
Root Diameter ◽  
Plant Spacing ◽  
Fresh Weight ◽  
Area Index ◽  
Leaf Dry Weight

Despite the existing several Sugar manufacturing companies in Sudan, there is an acute shortage in sugar supply, therefore the government imports Sugar to bridge the gap. One of the strategies to be followed is the introduction of Sugar beet (Beta vulgaris) crop, mainly for sugar production. This crop has several advantages over Sugarcane such as short duration, less water requirement, in addition to other uses like animal feed. Therefore it became necessary to have good understanding of agricultural operations, cultural practices and adaptation. However, the main objective of this study was to assess the effect of Nitrogen fertilizer and plant spacing on vegetative growth of Sugar beet. This study was conducted at the farm of the College of Agriculture, University of Bahri, Alkadro, Khartoum State-Sudan; during the season 2016/2017. The experiment was arranged in Split plot in Randomized Complete Block Design with six treatments and four replications. Two plant spacing (15 and 20 cm.) were used as main plot, referred as (S1, S2) along with three levels of Nitrogen fertilizer (40, 80 and 120 kg/ha.), as subplot; referred as (N1, N2 and N3) and the control (0). Data regarding leaf number, leaf area index (LAI), leaf dry weight (g) (LDW), root diameter (mm.) and root fresh weight were recorded and statistically analyzed. The results showed S2 (20 cm) increased all the studied plant characters, namely the leaf number (29.139), leaf area index by (7.54), leaf dry weight (g) to (89.870), root diameter (mm) (94,992), root fresh weight (g) (695.80) compared to S1(1015 cm). On the other hand; the application of N3 (120 kg/ha.) increased the lead number (30.956), leaf Area Index (8.841), Leaf dry weight (102.47), root diameter (97.955) and root fresh weight (851.77) compared to S2 and S1 as presented in (table 4, table 5 and table 6).

scholarly journals Growth Regulation of Sub-Tropical Perennials by Photoselective Plastic Films

2001 ◽  
Vol 19 (2) ◽  
pp. 65-68
Author(s):  
Sandra B. Wilson ◽  
Nihal C. Rajapakse
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Plant Species ◽  
Spectral Distribution ◽  
Growth Regulation ◽  
Dry Weight ◽  
Stem Length ◽  
Plastic Films ◽  
Control Film ◽  
Leaf Dry Weight

Abstract Plant response to photoselective plastic films with varying spectral distribution properties was tested using three sub-tropical perennials: golden shrimp plant (Pachystachys lutea), Persian shield (Strobilanthes dyerianus), and cat whiskers (Orthosiphon stamineus). Films were designated YXE-10 [far-red (FR) light-absorbing film] and SXE-4 [red (R) light absorbing film]. Light transmitted through YXE-10 films reduced plant height (stem length) of golden shrimp plant and cat whiskers by 10 and 20%, respectively. Light transmitted through SXE-4 films increased plant height by 9% for golden shrimp plant but did not significantly increase stem length of Persian shield and cat whiskers species. Chlorophyll, leaf area, and mean days to flower generally were not affected by photoselective films, with the exception that cat whisker plants grown under YXE-10 films had reduced leaf area when compared to plants grown under SXE-4 or control films. As compared to the control film, light transmitted through YXE-10 films reduced leaf dry weight by 22–31% and stem dry weight by 19–28%, depending on the plant species. Root dry weight was not affected by spectral films.

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