Leaf Fresh Mass Research Articles

Assessing ecosystem resilience: effects of different environments on native flora, lichens and bee pollen in a mid-sized Brazilian city

Abstract The alteration of the natural environment by human activities has increased in recent decades, with a significant impact on the organisms that inhabit it. One of the most apparent consequences of environmental alterations is the occurrence of climatic changes. The city of Joinville is situated in the southern region of Brazil. It has achieved a notable position at the national level, largely due to the significant presence of large-scale industrial operations in the metal-mechanical, plastic, and textile sectors. This study aimed to assess the effects of urban environments on Nectandra oppositifolia plants and lichen communities using a passive biomonitoring approach, and on Tetragonisca angustula stingless bees using an active biomonitoring approach. This study demonstrated a pronounced effect of anthropogenic activities on plant anatomy and morphology (higher leaf area, fresh mass, dry mass, and water content in the urban-industrial site), with higher metal concentrations in leaf particulate matter (3.14 ± 0.4 μg cm−2). The diversity of lichens was the lowest, whereas that of crustose lichens was the highest in industrial-urban and residential-rural sites (industrial-urban site = 13 species, residential-rural site = 29 species, control site = 33 species, p < 0.05). The distribution of species within the lichen communities was inversely correlated with the degree of anthropogenic influence. Some lichen species were found exclusively in the control areas, suggesting that they may indicate good environmental quality (Arthonia sp., Astrothelium sp., Phyllopsora pyxinoides, Phyllopsis sp., and others). Beehive pollen analysis revealed the presence of Zn, Cr, Ni, Cu, and Pb, and industrial-urban site exhibited higher metal concentrations (particularly, Ni, 12.59 ± 0.9, and Cr, 3.76 ± 1.00, mg kg−1). This approach highlights the environmental repercussions that affect the Plantae, Fungi, and Animalia kingdoms. The use of biomonitoring as a robust tool in good environmental quality assessment provides insight into policy decisions and underscores the importance of pollution studies.

The "Leafing Intensity Premium" Hypothesis and the Scaling Relationships of the Functional Traits of Bamboo Species.

The "leafing intensity premium" hypothesis proposes that leaf size results from natural selection acting on different leafing intensities, i.e., the number of leaves per unit shoot volume or mass. The scaling relationships among various above-ground functional traits in the context of this hypothesis are important for understanding plant growth and ecology. Yet, they have not been sufficiently studied. In this study, we selected four bamboo species of the genus Indocalamus Nakai and measured the total leaf fresh mass per culm, total non-leaf above-ground fresh mass, total number of leaves per culm, and above-ground culm height of 90 culms from each species. These data were used to calculate leafing intensity (i.e., the total number of leaves per culm divided by the total non-leaf above-ground fresh mass) and mean leaf fresh mass per culm (i.e., the total leaf fresh mass per culm divided by the total number of leaves per culm). Reduced major axis regression protocols were then used to determine the scaling relationships among the various above-ground functional traits and leafing intensity. Among the four species, three exhibited an isometric (one-to-one) relationship between the total leaf fresh mass per culm and the total non-leaf above-ground fresh mass, whereas one species (Indocalamus pumilus) exhibited an allometric (not one-to-one) relationship. A negative isometric relationship was found between the mean leaf fresh mass per culm and the leafing intensity for one species (Indocalamus pedalis), whereas three negative allometric relationships between mean leaf fresh mass per culm and leafing intensity were observed for the other three species and the pooled data. An exploration of the alternative definitions of "leafing intensity" showed that the total number of leaves per culm divided by the above-ground culm height is superior because it facilitates the non-destructive calculation of leafing intensity for Indocalamus species. These results not only confirm the leafing intensity premium hypothesis for bamboo species but also highlight the interconnected scaling relationships among different functional traits, thereby contributing to our understanding of the ecological and evolutionary significance of leaf size variation and biomass investment strategies.

Integrated cultivation of tambaqui (Colossoma macropomum) with coriander (Coriandrum sativum L.) grown at different plant density

The present study aimed to evaluate an aquaponic bioeconomic model integrating the cultivation of tambaqui (Colossoma macropomum) with coriander (Coriandrum sativum) at different densities of 32, 72, 128, and 512 cells m−2 for 19 days. The hydroponic bed was configured on a bench with a capacity of 100 L (1.62 m-long, 0.72 m-width, and 0.1 m-depth) and was coupled to a plastic tank with the fish. The coriander seeds were irrigated for four days until germination, when they were transferred to the hydroponic beds. Two hundred forty tambaqui juveniles (113.5 ± 0.15 g and 19.6 ± 0.20 cm) were distributed in 12 tanks (1000-L capacity) in aquaponic units, totaling 20 fish per unit. The fish were fed commercial feed (36% protein and 7% lipids), and water quality variables were monitored daily. At 5, 10, and 15 days after transplanting to the hydroponic bed, the leaf number (LN) and plant height (PH, in cm) of the coriander were determined. Additionally, total fresh mass (TFM, in g), leaf fresh mass (LFM, in g), root fresh mass (RFM, in g), total dry mass (TDM, in g), leaf dry mass (LDM, in g), root dry mass (RDM, in g), leaf length (LL, in cm), root length (RL, in cm), yield of total fresh mass (YTFM, in kg m−2), and the nutritional composition of macro and micronutrients were determined, as well as fish growth performance. A density of 512 cells m−2 reduced the electrical conductivity (0.097 ± 0.001 dS m−1) of the water. The pH, dissolved oxygen, and temperature did not differ significantly between the densities. The total ammonia nitrogen (28.81 ± 2.26 mg L−1) and nitrate (51.07 ± 0.81 mg L−1) concentrations were greater at a density of 32 cells m−2. At the end of the 19-day period, the fish growth indices did not significantly differ (p > 0.05) as a function of coriander cultivation density. Density significantly influenced coriander growth. All variables (PH with root, LL, RL, LFM, TFM, LDM, TDM, RFM, RDM, and YTFM) were significantly influenced (p < 0.05) as a function of cultivation density. YTFM (1.82 ± 0.45 kg m−2), PH (30.39 ± 0.61 cm), and LL (16.62 ± 0.53 cm) were significantly higher (p < 0.05) at a density of 512 cells m−2. RL was significantly higher (p < 0.05) at densities of 72 and 32 cells m−2, of the order of 15.98 ± 0.43 and 18.79 ± 1.01 cm, respectively. Boron was significantly greater at a density of 512 cells m−2 (39.70 ± 1.04 mg kg−1) than at 32 cells m−2 (29.93 ± 4.66 mg kg−1). Similarly, sodium was significantly more abundant at a density of 512 cells m−2 (5975.54 ± 783.82 mg kg−1) when compared to the densities of 128 and 72 cells m−2, which were 4179.97 ± 287.31 and 3760.60 ± 224.31 mg kg−1, respectively. Aquaponic production in the equatorial Amazon region accelerated, and the optimal density for coriander integrated with tambaqui without compromising plant growth performance was 128 cells m−2.

Cultivo de alface em diferentes sistemas hidropônicos e concentrações de nutrientes na solução nutritiva

ABSTRACT Alternative techniques for cultivation without soil are widespread; however, studies comparing hydroponic systems still need to be studied, mainly in semi-arid regions. The present study aimed to evaluate the effect of hydroponic systems on the yield and quality of lettuce cultivars subjected to different electrical conductivities of the nutrient solution. The research was conducted in a greenhouse, adopting a completely randomized design in a 2 × 2 × 3 factorial scheme, being two lettuce cultivars (Cinderela and Rubinela), two electrical conductivities (2.90 and 1.6 dS m-1), and three hydroponics systems (NFT, semi-hydroponic, and floating), with three replications. The number of leaves, leaf succulence, specific leaf area, leaf fresh mass, total dry mass, leaf area, titratable acidity, vitamin C, and soluble solids were evaluated. Cinderela cultivar showed the highest average leaf fresh mass, total dry mass, leaf area, and vitamin C values. The NFT and floating systems provided the highest leaf yield and quality, especially in the solution of 1.60 dS m-1. The semi-hydroponic system provided greater development of the plants with a more concentrated nutrient solution (2.90 dS m-1).

Temporal Separation of Red and Blue Photons Does Not Increase Photon Capture or Yield of Lettuce

Temporal separation of red (R) and blue (B) (alternating R/B) photons has been reported to increase leaf area, photon capture, and yield of lettuce compared with delivering both colors together (concurrent R+B). We grew three diverse lettuce cultivars (Grand Rapids, Rex, and Red Sails) under concurrent R+B photons (9/1 ratio) and alternating R/B photons (9/1 ratio) under an equal daily light integral (DLI) of either 8.6 or 23 mol⋅m−2⋅d−1. Contrary to five previous studies, we found no increase in either leaf area or fresh mass and dry mass in any of the alternating R/B photon treatments compared with concurrent R+B photons. In fact, at a DLI at 8.6 mol⋅m−2⋅d−1, alternating R/B photons decreased the dry mass of ‘Grand Rapids’ and ‘Rex’ lettuce by 38% and 17%, respectively. Two previous studies reported that photosynthetic rates increased with alternating R/B photons; however, we found that the net assimilation rate was generally decreased by alternating R/B photons. An analysis of images obtained from automated digital photography revealed that the relative expansion rate of leaves was 61% higher during intervals of pure B rather than intervals of pure R photons at the same photosynthetic photon flux density; however, this did not result in a higher leaf area compared with concurrent R+B photons. Overall, our studies do not indicate that alternating R/B photons increase lettuce leaf area or yield compared with concurrent R+B photons.

Functional leaf-trait variability and herbivory in oaks along a Mexican avocado agrosystem mosaic

Land-use changes transforming forested landscapes to avocado orchards affect abiotic conditions and ecological processes. As a consequence, such changes can also affect leaf functional traits expression of co-occurring trees in orchards and related plant–insect interactions. Here, we evaluated changes in chemical soil properties and the effects of micro-climatic variables on leaf functional traits and herbivory in Quercus castanea and Q. obtusata in fragments occurring in a mosaic with avocado orchards. We differentiate three cases: forest cover > orchards, forest cover = orchards and forest cover < orchards in Michoacan state, Mexico. In each case, at least 17 individuals of each oak species were selected to analyze leaf functional traits and herbivory. Soil samples were collected to analyze chemical properties. Soils of areas with higher proportion of forest had higher concentrations of NH4+ and K+, whereas soils with higher proportion of orchards displayed higher concentrations of Mg2+, NO3− and SO42−. Leaf thickness, fresh mass and water content were higher in areas with higher forest cover and were influenced by Mg2+, NO3−, SO42- and local climatic variables. Leaf dry weight, specific leaf area, leaf area and chlorophyll content, as well as herbivory were higher in areas with higher proportions of orchards and were affected by PO43−, total P, K+, NH4+, and by local climatic variables. These results highlight the responses and links of plant functional traits associated with soil properties and local climatic variables and their possible consequences of biotic interactions in a landscape mosaic with different covers of avocado orchards and temperate forests.

Evaluating the relationship between stem and leaf biomass as well as stem length and leaf surface area of amaranth cultivars in improving food plant

Amaranth is now cultivated almost all over the World for multiple purposes, such as a vegetable, seed food, feed for animals, medicine, and for industry uses. They are highly nutritious, with vitamins and minerals. Leaf area and leaf dry biomass are key parameters linked to plant growth and production. The relationship between leaf biomass and leaf surface area, as well as stem biomass and stem length, is important to our understanding of plant scaling relationships because of their relationship to plant survival. This paper aimed to evaluate the relationship between and within the leaf and stem parameters of nine different amaranth cultivars. The fresh leaves and stems were weighed in their fresh masses; the surface area for leaves was calculated by drawing a full leaf in square quadrats and then counting the square quadrats occupied by a leaf and the stem length was measured using a ruler. Our results indicated that there was a clear relationship between leaf fresh mass and leaf dry mass but a negative correlation between stem fresh mass and stem dry mass due to different internal contents such as water and substances. A low significance was obtained between leaf biomass and leaf surface area, stem biomass and stem length, and leaf biomass and stems biomass as well as leaf surface area and stem length. Our results revealed that this variability of values causes the disproportional ratio of fresh mass to dry mass due to the differentiation quantity of water and solutes within the leaves and stems.

Estimativa da ploidia e pré-seleção de autotetraploides de bananeira após indução da poliploidia in vitro

ABSTRACT This study aimed to evaluate the efficiency of the parameters fresh leaf mass and stomatal density in the estimation of ploidy and pre-selection of putative banana autotetraploids. Young plants of the diploid cultivar Ouro (AA), previously subjected to in vitro polyploidization with the antimitotic amiprofos-methyl - APM (0, 10, 20, 30, 40, and 60 µM L-1) and colchicine (2.5 mM L-1) were evaluated for survival, height, number of leaves, pseudostem diameter, leaf disc fresh mass, and stomatal density. Ploidy was determined by flow cytometry in a random sample of 200 plants to find the relationship between the genomic content and the analyzed variables. Spearman’s correlation analysis showed a strong correlation (0.84**) between leaf disc fresh mass and tetraploid plants, as well as an absence of significant correlation between stomatal density and ploidy levels. Thus, the pre-selection of plants was carried out using a reference value of leaf disc fresh mass and resulted in 688 plants pre-selected as putative tetraploids. Among them, 318 were confirmed as tetraploids, 291 as diploids, and 79 as mixoploids after flow cytometry analysis. The pre-selection efficiency was 46.2% of tetraploid plants from the total pre-selected. The results indicate that the use of leaf disc fresh mass is a simple, practical, and promising method to estimate ploidy when a high number of plants is obtained in in vitro banana polyploidization studies, reducing the total number of plants to have confirmed ploidy.

Water use efficiency, morpho-physiological and biochemical reactions of some bedding plants to drought stress

The purpose of this experiment is to compare the growth and water consumption efficiency of five garden plants (marigold (Tagetes erecta ‘Red Brocade’), moss-rose (Portulaca grandiflora ‘Sun Rose’), dahlia (Dahlia sp. ‘Double Opra’), gazania (Gazania splendens ‘New Day’), and Indian blanket (Gaillardia pulchella. ‘Sun Dance’)) during the warmer seasons of the year under various levels of drought stress based on field capacity (FC; 25, 50, 75, and 100 %). The interaction effect of plant × drought stress (FC) on the fresh and dry mass of aerial and underground organs was significant. Decreased water availability resulted in a drop in growth parameters (leaf fresh and dry mass and leaf area). In compared to the growth of aerial organs, root biomass increased in response to drought stress. Marigold, Indian blanket, and dahlia plants had the highest root-to-shoot ratio in extreme stress, i.e., FC 25 %. The plant × drought stress interaction significantly influenced flower number, whereas flower diameter was influenced by the main effect of plant and drought stress (not their interaction). The FC 100 % and FC 25 % treatments had the highest and the lowest accumulations of proline and soluble sugars, respectively. Moss-rose, gazania, and marigold ornamental plants had the highest water use efficiency at 75 %, followed by Dahlia at 50 % and moss-rose at 25 %.

A novel approach to achieving more efficient production of the mature form of human IL-37 in plants.

Interleukin-37 is a newly discovered cytokine that plays a pivotal role in suppressing innate inflammation and acquired immunity. We have recently expressed both the mature(mat-) and pro-forms of human IL-37b in plants and demonstrated that while both forms of the plant-made hIL-37b are functional, pmat-hIL37b exhibited significantly greater activity than ppro-IL-37b. Compared to ppro-hIL-37b, on the other hand, the expression level of pmat-hIL-37b was substantially lower (100.5µg versus 1.05µg/g fresh leaf mass or 1% versus 0.01% TSP). Since the difference between ppro-hIL-37b and pmat-hIL-37b is that ppro-hIL-37b contains asignal sequence not cleavable by plant cells, we reasoned that this signal sequence would play a key role in stabilizing the ppro-hIL-37b protein. Here, we describe a novel approach to enhancing pmat-hIL-37b production in plants based on incorporation of a gene sequence encoding tobacco etch virus (TEV) protease between the signal peptide and the mature hIL-37b, including a TEV cleavage site at the C-termini of TEV protease. The rationale is that when expressed as a sp-TEV-matIL-37b fusion protein, the stabilizing properties of the signal peptide of pro-hIL-37b will be awarded to its fusion partners, resulting in increased yield of target proteins. The fusion protein is then expected to cleave itself in vivo to yield a mature pmat-hIL-37b. Indeed, when a sp-TEV-matIL-37b fusion gene was expressed in stable-transformed plants, a prominent band corresponding to dimeric pmat-hIL-37b was detected, with expression yields reaching 42.5µg/g fresh leaf mass in the best expression lines. Bioassays demonstrated that plant-made mature pmat-hIL-37b is functional.

Light supplementation and growing season affect the quality and antioxidant activity of lettuce

The light spectrum plays a major role in regulating plant growth and development, influencing photosynthesis and photo-morphogenesis. The objective was to evaluate the weight and antioxidant activity of ‘Lavinia’ lettuce (Lactuca sativa L. var. capitata L.) plants under LED lights with different red:blue ratios (R:B) used as a supplement to ambient light in a greenhouse at different seasons. Five LED light supplemented treatments were used, white (W, as control, ratio blue:green:red:far-red (B:G:R:Fr) = 30:45:20:5; 0.7:1.0), blue (B = 50:20:20:10; R:B = 0.4:1.0), white-r (Wr = 25:30:40:5; 1.6:1.0), white-R (WR = 15:15:63:7; 4.2:1.0) and red (R = 10:10:75:5; 7.5:1.0) were applied in early autumn, late autumn and winter. Immediately after transplant into the hydroponic system, lettuces plants with 3-4 true leaves (5-6 cm root length) were treated with light treatments for 14 d and harvested. In early autumn, late autumn, and winter, the PAR range applied in ambient light and supplemental lights was between 361 to 495, 222 to 304, and 297 to 407 µmol m-2 s-1, respectively. Lettuce showed the highest fresh leaf mass in early autumn compared to late autumn and winter due to the highest leaf number. In early autumn, only lettuce under the highest R:B (7.5:1.0) had a lower weight among the light treatments. Overall, lettuces supplemented with R:B between 1.6 (Wr) to 4.2 (WR) had significantly higher DM than the control (0.7:1.0). Total phenolic contents (TPC) and antioxidant capacity (AC) were highest in early autumn, followed by winter and late autumn. Light with the highest R:B (7.5:1.0) diminished TPC and AC in all growing season. This study showed that the quality of ‘Lavinia’ lettuce plants grown in early autumn under R:B between 1.6 and 4.2 improved DM, and higher red component decreased the antioxidant activity.

Initial development of maize plants grown with different combinations of nitrate and ammonium

Corn is one of the main commodities of Brazilian agribusiness, due to its wide use, whether for human or animal consumption or in the chemical and biofuel industries. Thus, this work was carried out to evaluate the influence of different proportions of nitrate and ammonium in the initial development of corn plants. The experiment took place in a greenhouse, by direct sowing, where the seeds were placed at a depth of 1 cm in plastic pots with a capacity of 6 dm3 containing a mixture of previously sieved and washed with vermiculite, in a 2:1 ratio. Five proportions of nitrate and ammonium ions (NO3- :NH4+) were used: T1=100:0, T2=75:25, T3=50:50, T4=25:75 and T5=0:100, through nutrient solutions. After 35 days of cultivation, the following were evaluated: plant height, number of leaves, culm diameter, chlorophyll a, b, total and a/b ratio, root length, leaf fresh matter mass, dry matter mass of leaves, culm, roots, total dry mass, and root dry mass/shoot dry mass ratio, leaf area, specific leaf area, leaf area ratio, and leaf mass ratio. Nitrate as the only source of nitrogen provided a smaller increase in the chlorophyll a index of maize plants, which is the most important chlorophyll in the capture of light in the antenna complex. It is not recommended to cultivate corn plants with only nitrate or ammonium; however, it was observed that high doses of nitrate combined with low doses of ammonium in the culture medium provided satisfactory performance for most variables.

Potential of Desmodesmus abundans as biofertilizer in common bean (Phaseolus vulgaris L.)

Microalgae are source of macro- and micronutrients, phytohormones, lipids and carbohydrates, in addition to having an excellent adaptive capacity to the most diverse environments. Due to this, they have gained prominence in the biofertilizer industry. In this work, we evaluated the potential Desmodesmus abundans L2B Bold biofertilizer in bean cultivar “Pérola”. Microalgal biomass (107 cells mL−1) was applied to bean plants by manual irrigation starting at 15 days after sowing (DAS) and then every 10 days thereafter. The total number of pods and seeds, leaf fresh and dry mass, root dry mass, and total fresh and dry mass were positively influenced by microalgae biofertilizer. The leaf pigments were significantly (p < 0.05) increased with the use of D. abundans L2B Bold. This increase was of approximately 30% in chlorophyll a and b content with the application of biofertilizer 17 DAS and 7% in the middle of the crop cycle (37 DAS). The biofertilizer also significantly (p < 0.05) impacted foliar enzymatic activity with superoxide dismutase (SOD) being increased during all the crop cycle. Phenylalanine ammonia-lyase (PAL) presented higher activity under microalgae use, being increased approximately 120%–1500% in biofertilized plants in the middle and at the end of the crop cycle, respectively. There were significant(p < 0.05) increases in K and Ca of seed beans contents with the application of biofertilizer. Based on our results, we conclude that D. abundans L2B Bold has great potential for use as a biofertilizer in bean crop.

Divergent adaptations of leaf functional traits to light intensity across common urban plant species in Lanzhou, northwestern China.

Leaves are the most important photosynthetic organs in plants. Understanding the growth strategy of leaves in different habitats is crucial for elucidating the mechanisms underlying plant response and adaptation to the environment change. This study investigated the scaling relationships of the laminar area (LA), leaf fresh mass (LFM), leaf dry mass (LDM), and explored leaf nitrogen (N) and phosphorus (P) content in leaves, and the relative benefits of these pairwise traits in three common urban plants (Yulania denudata, Parthenocissus quinquefolia, and Wisteria sinensis) under different light conditions, including (full-sun and canopy-shade). The results showed that: the scaling exponent of LDM vs LA (> 1, p < 0.05) meant that the LDM increased faster than LA, and supported the hypothesis of diminishing returns. The LFM and LDM had isometric relationships in all the three species, suggesting that the leaf water content of the leaves was nearly unaltered during laminar growth. Y. denudata and W. sinensis had higher relative benefit in full-sun habitats, while the reverse was observed in P. quinquefolia. The N and P content and the N:P ratio in full-sun leaves were generally higher than those of canopy-shade leaves. The leaves of the three urban plants exhibited a shift in strategy during transfer from the canopy shaded to the sunny habitat for adapting to the lower light conditions. The response of plant leaves to the environment shapes the rich variations at the leaf level, and quantification of the relative benefits of plants in different habitats provides novel insights into the response and adaptation strategies of plants.

Chicória da Amazônia: cultivo a pleno sol ou sombreado?

ABSTRACT Climatic factors can decisively influence the growth and productivity of agricultural crops. For unconventional vegetables, such as the Amazon chicory, the influence of sunlight on growing cycle is unknown. The aim of this study was to evaluate the influence of shading levels on the productive performance of Amazon chicory. The authors used a randomized block design, with four treatments and five replicates. The treatments were black polypropylene screens, 30, 50 and 70% shading, and cultivation at full sunlight. Vegetative development and production traits were evaluated. Correlation and principal components analysis (PCA) were performed with the aid of the computer program R. No significant difference between the shading levels for the evaluated traits was noticed. Nevertheless, the cultivation at full sunlight allowed an increase in production, compared to the 70% shading screen. A strong positive correlation between productivity, leaf fresh mass and amount of water in the shoot area was verified, with a coefficient equal to 1. Only the leaf area characteristic was poorly correlated with other traits (angle &gt;90º). Therefore, we suggest growing the Amazon chicory both at full sunlight and under 70% shading.

Respostas morfofisiológicas de plantas matrizes de cafeeiro conilon em jardim clonal superadensado

Abstract The objective of this work was to evaluate the morphophysiological responses and cutting production of clones of Conilon coffee (Coffea canephora) cultivars in a super-dense clonal garden in the state of Espírito Santo, Brazil. The super-dense clonal garden was built in 2019 using 39 clones: 9, 9, 9, and 12 of cultivars Centenária ES8132, Diamante ES8112, ES8122 (Jequitibá), and Marilândia ES8143, respectively. The experiment was carried out in a randomized complete block design, with three replicates. Cutting production and the following morphophysiological traits were evaluated at 9 and 18 months after planting: chlorophyll index, normalized difference vegetation index, plant height, canopy height, canopy diameter, number of shoots, number of viable cuttings, number of leaves, fresh leaf mass, and plant fresh and dry matter mass. The super-dense clonal garden caused different morphophysiological responses among the studied clones. In general, clones C2, C5, C6, C8, D1, D8, D9, J8, M2, M9, M10, and M12 showed a higher mean cutting production, whereas C4, J1, J4, M4, and M5 were the most sensitive to the super-dense regime. Under these conditions, it is recommended to increase the proportion of matrix plants of the latter clones.

Effects of Led Light Intensity and Carbon Dioxide Concentration on the Growth of Spinach (Spinacia oleracea L.) in a Plant Factory

This research aimed to investigate the effects of light intensity and the carbon dioxide (CO2) concentration on spinach’s growth during vegetative stage in plant factory (PF). Two experiments were conducted with different CO2 concentration in closed chamber (500 ppm and 800 ppm). In each experiment, plants were hydroponically grown under three light intensities of 115, 140 and 160 µmol.m-2s-1. Growth’s parameters were determined at different growth stages (T30, T37 and T44 respectively to 30, 37 and 44 days after sowing). ANOVA analysis and non-parametric Kruskal analysis of variance were used to evaluate the statistical significance of the treatment effects. The results showed that, before 30 days old, the increase of light intensity was not significantly effected to the growth of plant. During later growing periods (30 days old afterward), the increase of light intensity remarkably boost up yield’s related traits such as leaf number, fresh mass and dry mass under 500ppm CO2 concentration. The combination of light intensity and CO2concentration at 800ppm showed the plant growth indicators increased significantly at the T37 and T44 stages (after 30 days old), especially at the last week of growth period, fresh weight and dry weight of plants were significantly different at the light treatment L2, increased 37% and 57.6%, respectively as compared to light treament only. The results suggested that, during latest growing period, the average light intensity of 140 µmol.m-2s-1combining with elevating CO2 concentration is an alternatively way to enhance spinach growth. The findings of this study could be helpful for growers to improve growing conditions for a better development of spinach in the indoor farming (PF)&#x0D;

Do the same genus plants have consistent adaptation strategies in cold-wet environments? A case study of leaf suitability of 19 Syringa species

Carbon cost-benefit theory indicates that leaf photosynthesis benefit and structure cost have scaling relationship. However, this relationship has not been tested in the perennial cold-wet regions. Shorter growing seasons in cold-wet climates severely limit plant growth, making it important to explore the light interception and economic strategies for the survival of plants in this region. We measured leaf area (LA), leaf fresh mass (LFM) and leaf dry mass (LDM) of 19 Syringa species around Xi’ning city to explore leaf scaling relationship and adaptation strategies. Our results showed that LA, LFM and LDM varied among species, with the coefficients of variation (CV) among species being 64.61%, 76.43% and 65.94%, respectively. For all species, LDM with LFM and LA showed isometric growth, and only LA and LFM followed allometric growth with a scaling exponent greater than 1 (p < 0.05). Linear correlation indicated that, with the increase of LA, the scaling constant tended diminishingly. Ultimately, according to the CSR (Competitor - Stress tolerator - Ruderal) strategy division, nineteen plants were divided into strategy CS (competitor & stress tolerator) and strategy S/CS (stress tolerator/competitor & stress tolerator). What’s more, LA, LFM and LDM of CS strategy plant were all significantly greater than S/CS strategy. In conclusion, plants in cold-wet habitats tend to have a more conservative economic strategies; and combined with the CSR theory, these plants are more competitive and stress tolerators. More attention should be paid to the effects of harsh environments on plant life history strategies.

Morphophysiological and productive changes of onion under vitamin application

Studies have been developed to improve cultivation conditions through the introduction of beneficial compounds, among which are vitamins. The present work aimed to investigate the effects of the application of vitamins in the onion crop. For that, five treatments were used, composed of different vitamins (ascorbic acid, thiamine, niacin and pyridoxine), in a concentration of 100 mg L-¹ and a control treatment, with water application, via foliar spray. The characteristics of chlorophyll relative index, number of plant leaves, plant height, fresh leaf mass, leaf dry mass, bulb diameter, bulb mass and bulb yield were evaluated. It was found that the application of ascorbic acid and pyridoxine increased the relative levels of chlorophyll concerning the control treatment and those composed by the application of niacin and thiamine. In addition, for liquid photosynthesis, a superior result was shown when niacin and thiamine were applied, concerning the other treatments. It was concluded that the exogenous application of vitamins alters the physiological and developmental behavior of onion plants, but does not positively affect bulb yield. The increases in photosynthetic activity were not reversed in bulb development, but in the elongation of plant leaves. Finally, the use of the vitamins studied for onion cultivation is not recommended, under conditions similar to those of the present study.

PLANTING FERTILIZATION AND NITROGEN DOSES IN TOPDRESSING IN SECOND-CROP CORN

The present study aimed to evaluate the influence of fertilization formulated at planting and doses of nitrogen in topdressing on the yield components of second-crop corn. The experiment was conducted between March and June 2018 on the farm of the State University of Goiás, University Unit of Ipameri-GO. The randomized block design, arranged in a 3 x 5 factorial scheme with four replications, was used. Three fertilizer formulations at planting (06-22-12; 08-20-15 and 06-22-12 + 2% organic carbon) and five doses of N (0, 50, 100, 150 and 200 kg ha-1) in topdressing were evaluated. Leaf nitrogen content, fresh and dry mass of leaves, plant height, stem diameter, first ear insertion height, length and diameter of ears, 1000-grain weight, the mass of plants per hectare, extraction of nitrogen, and grain yield were assessed. Given the results, NPK formulated fertilizers can be used indifferently to grow second-crop corn. Nitrogen doses in topdressing have satisfactory results up to the estimated rate of 135 kg ha-1 for the cultivation of second-crop corn.