Root Dry Mass Research Articles

Screening Bambara Groundnut (Vigna subterranea L. Verdc) Genotypes for Drought Tolerance at the Germination Stage under Simulated Drought Conditions.

Bambara groundnut (Vigna subterranean L. Verdc) is grown by smallholders and subsistence farmers in the marginal parts of sub-Saharan Africa. This legume is native to Africa and is cultivated throughout semi-arid sub-Saharan Africa. It is hardy and has been recognized as a nutritious food source in times of scarcity. Drought can negatively affect the germination or establishment of seedlings in the early stages of crop growth. Drought can limit the growing season of certain crops and create conditions that encourage the invasion of insects and diseases. Drought can also lead to a lack of crop yield, leading to rising food prices, shortages, and possibly malnutrition in vulnerable populations. A drought-tolerant genotype can be identified at the germination stage of Bambara groundnut by screening for drought-tolerance traits, and this knowledge can be applied to Bambara crop improvement programs to identify drought-tolerant traits during early growth phases. As an osmolyte, polyethylene glycol (PEG 6000) reduced water potential and simulated drought stress in Bambara groundnut seeds of different genotypes. Osmolytes are low-molecular-weight organic compounds that influence biological fluid properties. In this study, 24 Bambara groundnut genotypes were used. Data were collected on seed germination percentage (G%), germination velocity index (GVI), mean germination time (MGT), root dry mass (RDM), root fresh mass (RFM), and seven drought tolerance indices: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), stress susceptibility index (SSI), yield index (YI), yield stability index (YSI), stress tolerance index (STI) as well as seed coat color measurements. The data were applied to the mean observation of genotypes under simulated drought conditions (Ys) and the mean observation of genotypes under controlled conditions (Yp). Germination%, germination velocity index (GVI), mass germination time (MGT), and root fresh mass (RFM) differed significantly (p < 0.001) between the two stress conditions. Bambara genotypes Acc 82 and Acc 96 were found to be the most drought-tolerant.

Initial Growth of Sesame under Nutrient Omission

Sesame is an oilseed, nutritionally important in the world, for its seeds are rich sources of protein and calcium. Fertilizer management is fundamental for the development of this crop and consequently to increase its productivity. In this context, this research aimed to evaluate the initial development of sesame under nutrient omission in the Cerrado of Mato Grosso, Brazil. The experiment was conducted under controlled conditions in a greenhouse, at the Federal University of Rondonópolis. The soil used was Oxisol and the crop used was black sesame. The design was in randomized blocks, with five treatments (absence of nitrogen, absence of phosphorus, absence of potassium, complete fertilization and control (absence of nutrients)) and four repetitions. The variables analyzed were pH, chlorophyll index, plant height, number of leaves, stem diameter, leaf area, aboveground dry mass, root volume, and root dry mass. The pH variable showed a statistical difference 45 days after emergence. The chlorophyll index showed a difference between 30 and 45 days after emergence. The stem diameter, leaf area, plant height, number of leaves, aboveground dry mass, root volume, and dry mass showed a difference among treatments. The absence of nitrogen, phosphorus, and potassium significantly affects the initial development of sesame.

Agroeconomic response of inoculated common bean as affected by nitrogen application along the growth cycle

Biological nitrogen fixation (BNF) is an alternative for the supply of N, aiming at reducing production costs and environmental impacts of common bean crops. This work aimed to evaluate the agroeconomic performance of the inoculated common bean subjected to N-fertilizer application at different phenological phases. N-fertilizer, in a total of 90 kg ha-1 as urea, was applied at 3 phases: planting (P), phenological phase V4 (V4), and phenological phase R5 (R5) of the common bean, in two field experiments. The used treatments were: P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530, and P90V40R50. All treatments were inoculated with peat inoculum containing the commercial strain SEMIA 4077 (Rhizobium tropici). The number of nodules (NN), nodule dry mass (NDM), leaf area index (LAI), root dry mass (RDM), shoot dry mass (SDM), grain yield (GY), production cost (PC), gross revenue (GR), net revenue (NR), and benefit-cost ratio (BCR) were determined. Inoculated treatment (P0V40R50) showed higher NN and NDM. Although inoculated treatment (P0V40R50) showed lower values of LAI, RDM, SDM, and GY, inoculation can result in GR, NR, and BCR equal to N-fertilized treatments, depending on the prices achieved for grains sale.

Investigating soil properties and vegetation parameters in different biochar-amended vegetated soil at large suction for application in bioengineered structures

Bioengineered structures, such as landfill cover, vegetated slopes or embankments, green roof and turf are comprised of soil and vegetation where vegetation imparts stability and protection through root reinforcement and hydrologic action. Soil in bioengineered structures often compacted and subjected to prolong drying due to irregular irrigation which necessitates the investigation of soil properties and vegetation growth in biochar-amended soil (BAS) under large suction range and it is scarce in the literature. In the present study, the effect of different biochar types on soil properties, and the vegetation growth in compacted soil and under large suction range was investigated for application in bioengineered structures. The results revealed that the biochar amendment decreased the dry density (5-32%) and increased the water retention capacity (θs by 15-104%, θ1500 by 82-445% and plant available water content (PAWC) by 22-55%), pH (28-77%) and cation exchange capacity (CEC, 16-723%) of the soil. Further, the vegetation growth i.e., vegetation density, dry root mass and shoot mass increased by 8-13%, 33-108% and 4-157% respectively after biochar amendment. The vegetation wilting was started at a higher suction (~ 900kPa) relative to bare soil (800kPa), the permanent wilting point (PWP) increased (by 3-35%) and the complete photosynthetic activity remained unchanged at a higher suction (1600kPa) relative to bare soil (1050kPa) after biochar amendment. Among the biochar types i.e., Sugarcane Bagasse biochar (SBB), Mesquite biochar (MB) and Water Hyacinth biochar (WHB) tested, the MB showed the best performance i.e., the suitable vegetation growth and health status. The improved water retention due to increased porosity, specific surface area (SSA) and presence of hydrophilic functional groups, and the higher pH, CEC and lower dry density in BAS attributed to the higher vegetation growth. The findings of the present study suggest the application of BAS in bioengineered structures.

Single inoculation with arbuscular mycorrhizal fungi promotes superior or similar effects on cowpea growth compared to co-inoculation with Bradyrhizobium

• The single inoculation of R. clarus and C. etunicatum promoted the accumulation of nitrogen in the aerial part of both cultivars. • Inoculation with C. etunicatum resulted in higher phosphorus content in the shoot of the BRS Guariba cultivar. • Plants inoculated with C. etunicatum had similar or superior performance to plants fertilized with NPK or P. This study evaluated the efficiency of arbuscular mycorrhizal fungi (AMF) and the effect of co-inoculation with Bradyrhizobium on mineral accumulation and growth of two cowpea cultivars. The experimental design was a 12 × 2 factorial arranged in a completely randomized design, with four replications. The first factor consisted of 12 nutrient treatments: one control, four with AMF ( Rhizophagus clarus and Claroideoglomus etunicatum , inoculated individually and as a mixture, and AMF-based commercial inoculum) and four with AMF + rhizobia ( Bradyrhizobium sp. BR 3262); the second factor included two cowpea cultivars (BRS Novaera and Guariba), totaling 96 plots. Morphophysiological traits of plants, nitrogen and phosphorus accumulation in the aerial part, and symbiotic efficiency of microorganisms were evaluated. Double inoculation with C. etunicatum and R. clarus and the co-inoculation with Bradyrhizobium had no effect on height, shoot dry mass and N contents in the shoot of cowpea when compared to single inoculation with AMF. Positive effects of co-inoculation with Bradyrhizobium were verified for root dry mass in the treatments CE+B.BR 3262 and RC+CE+B.BR 3262, and for chlorophyll index and phosphorus content of the cultivar BRS Novaera in the nutrient treatment RC+CE+B .BR 3262. The nutrient treatment with single inoculation of R. clarus and C. etunicatum promoted the accumulation of nitrogen in the shoot for both cultivars. For the BRS Guariba cultivar, inoculation with C. etunicatum also resulted in higher phosphorus content. Overall, plants inoculated with C. etunicatum had a performance similar or superior to plants fertilized with NPK or P, resulting in greater mycorrhizal efficiency, which may be an alternative to conventional fertilization for cowpea cultivars BRS Novaera and BRS Guariba.

Emergence and initial growth of açaí palm under different light levels after seed dormancy breaking treatments

Light availability and dormancy are two factors that interfere with germination and initial plant growth. This study aimed to evaluate the influence of different pre-germination treatments on the emergence and initial growth of Euterpe oleracea Mart. seedlings subjected to different levels of luminosity. A completely randomized design was adopted in a 4 × 3 factorial scheme with four methods of overcoming dormancy (intact seed, hot water at 60 °C, soaking for 24 h in water, and mechanical scarification with sandpaper No. 100) and three levels of luminosity (25 %, 65 %, and 100 %) with 16 repetitions per treatment. The emergence percentage, speed index, and mean time were analyzed. The initial growth was evaluated using the following variables: plant height, stem diameter, shoot dry mass, root dry mass, total dry mass, leaf area, and root mass ratio. There was an interaction between light factors and dormancy breakage for plant height, stem diameter, and leaf area. The variables root dry mass, shoot dry mass, and root mass ratio showed better results with full sun. It was concluded that shade treatments provided greater initial growth for the açaí palm with intact seeds.

Allometric equations to estimate the dry mass of Sahel woody plants mapped with very-high resolution satellite imagery

Very high-resolution satellite images and deep learning are achieving the mapping of individual trees and shrubs over large areas in Africa. Each woody plant is precisely georeferenced and defined by its crown area and, sometimes, its height. The challenge is to build allometric equations for foliage, wood and root dry masses based either on crown area alone, or the product crown area × tree height as independent variables regardless of species. This was met by reanalyzing existing Sahel woody plant data from destructive sampling. Overall, the foliage (seasonal maximum), wood and root dry masses were measured on 900, 698 and 26 trees or shrubs from 27, 26 and 5 species respectively. The regression models tested for foliage, wood or root masses were linear or power functions using a range of different approaches: Ordinary least square (OLS) regression after log–log transform with or without Baskerville correction (1972), and non-linear regressions (NLR). All the models outputs were intercompared for fit indicators and prediction uncertainty, as well as the resulting trends in root to wood ratio, and foliage to wood ratio over the range of crown areas. This process selected a set of OLS log–log equations with crown area as independent variable. When the Baskerville correction is applied the approximation errors are 0.4 kg Dry Matter (DM) for foliage, 12.2 for wood and 6.3 for roots, aggregating at 13.8 kg DM per tree. These allometry equations were compared to published equations for tropical trees, most from the more humid tropics that were generally based on stem diameter, tree height and wood density. This paper’s allometry predictions were within the range of these other allometry equations, reinforcing the confidence in their use even beyond the Sahel domain towards sub-humid savannas.

Pinkish-achened form of Taraxacum hybernum Steven – a source of inulin and high molar mass natural rubber

ABSTRACT Taraxacum hybernum Steven (Asteraceae family) native to Southeast Europe is a promising rubber-bearing dandelion species. In the 1930s, several phenotypically distinct forms were described in this dandelion, such as brown-achened and pinkish-achened. More than 70 years after termination of research of temperate zone rubber-bearing plants we were able to find both forms of this species of dandelion in natural habitat. The species is still poorly studied, and there is no information about the differences in the quality and quantity of rubber between brown-achened and pinkish-achened forms. Therefore, the purpose of our study was to analyze the root morphology and yield, the rubber and inulin content, and to determine the molar mass of rubber in brown-achened and pinkish-achened T. hybernum. These two forms of T. hybernum, as well as T. kok-saghyz Rodin and T. brevicorniculatum Korol., were studied. The results show that the root shape most attractive for domestication is typical of brown-achened T. hybernum. The greatest mass of roots was gained for pinkish-achened T. hybernum. The rubber content was about 6% in T. kok-saghyz, 3% in both forms of T. hybernum, and 1.5% in T. brevicorniculatum per dry root mass. Taraxacum kok-saghyz and pinkish-achened T. hybernum turned out to be the leaders in inulin content. Of all four dandelions, the molar mass of rubber was more than 1 million g/mol only for T. kok-saghyz and pinkish-achened T. hybernum. Pinkish-achened T. hybernum is a good alternative for T. kok-saghyz and can be recommended for domestication and cultivation in the temperate zone.

ПРОДУКТИВНОСТЬ И АДАПТИВНОСТЬ СОРТОВ ЯРОВОЙ ПШЕНИЦЫ КОМПАНИИ КВС В УСЛОВИЯХ ПРЕДКАМЬЯ РЕСПУБЛИКИ ТАТАРСТАН

Increasing the yield and quality of the obtained grain of spring soft wheat on gray forest soils remains relevant. The purpose of the study is to identify the most productive variety of spring wheat of the KWS company in the conditions of gray forest soils of the Ancestral region of the Republic of Tatarstan. Field experiments and laboratory studies were conducted in 2020-2021 on gray forest soils by Agrobiotechnopark LLC at the Kazan State Agrarian University. Agrochemical indicators of the soil were as follows: humus content of more than 3.0%, mobile phosphorus (more than 250 mg/ kg according to Kirsanov), exchangeable potassium (121-170 mg/kg). The reaction of the soil medium is pH 6.6. The dry mass of roots and stems at the end of the tillering phase in the varieties KWS Torridon, KWS Aquilon, KWS Buran were significantly greater than in the variety Ulyanovsk 105, and the development and spread of root rot in the variety Ulyanovsk 105 is slightly higher than in the varieties KWS. In 2020, an increase in the number of productive stems was observed in the KWS Torridon variety to 584 pieces/m2, in the KWS Aquilon variety to 606 pieces /m2, in the KWS Buran variety to 591, while in the Ulyanovsk 105 variety only 480 pieces/ m2. The number of grains in the ear and the weight of grain from 1 ear in the KWS varieties were formed more than in the Ulyanovsk 105 variety, which subsequently contributed to obtaining significant yields from them. In the normally wet 2020, the KWS Torridon variety provided 1.0 t/ha of increase compared to the Ulyanovsk 105 variety, the KWS Aquilon variety – 1.39 t/ha, the KWS Buran variety – 1.43 t/ha, but the quality of the resulting grain did not meet the standard value of Class 3.

Salix gordejevii females exhibit more resistance against wind erosion than males under aeolian environment.

Effects of wind erosion on growth and adaptability have been widely reported in many plants, but little attention has been paid to dioecious plants. Recent studies have shown that sex-specific responses to environmental changes in many plants exist. To explore sexual differences in response to wind erosion, female and male Salix gordejevii saplings growing on inter-dune land (no erosion) and on the windward slope of the dune (20cm wind erosion) in Hunshandake Sandy Land were chosen and their morphology, biomass and physiological traits were investigated, respectively. Wind erosion significantly reduced plant growth, biomass accumulation, gas exchange and chlorophyll fluorescence, and obviously disrupted osmotic regulation function and antioxidant enzyme system in both sexes, especially in males. Under wind erosion condition, females exhibited higher sapling height (SH), basal diameter (BD), leaf dry mass (LDM), root dry mass (RDM), total dry mass (TDM), root percentage in total dry mass, net photosynthesis rate (P n), maximum efficiency of photosystem II (F v/F m), effective quantum yield of PSII (Φ PSII), relative water content (RWC) of leaves, superoxide dismutase (SOD) and peroxidase (POD) activities, but lower malondialdehyde (MDA), proline as well as soluble sugar content than did males. However, no significant sexual differences in most of these traits were observed under no erosion condition. Our results demonstrated that females possess a greater resistance to wind erosion than do males, with females having a better photosynthetic capacity, stronger water retention capacity and more efficient antioxidant system to alleviate negative effects caused by aeolian environment.

Effect of Indole-3-Acetic Acid on Tomato Plant Growth.

Plant growth-promoting bacteria have several abilities to promote plant growth and development. One of these skills is the synthesis of indole-3-acetic acid (IAA), which mainly promotes root and shoot development. The bacteria Bacillus subtilis and Azospirillum brasilense have been widely used in agriculture with this function. However, little is known about whether the joint inoculation of these bacteria can reduce plant development by the excess of IAA produced as a result of the joint inoculation. The objective of the present study was to verify the effect of IAA on the inoculation of B. subtilis and A. brasilense in three tomato genotypes. The Micro-Tom genotype without mutation for IAA synthesis, Entire, has high sensitivity to IAA, and the diageotropic genotype (dgt) has low sensitivity to IAA. The results show that the plant parameter most sensitive to microbial inoculation is the number of roots. No treatment increased the shoot dry mass parameters for the Micro-Tom genotype and dgt, root dry mass for the Micro-Tom genotype, plant height for the Micro-Tom and Entire genotypes, root area and root volume for the genotype dgt. The Azm treatment reduced plant height compared to the control in the dgt, the BS + Azw and BS + Azm treatments in the Micro-Tom genotype and the Azw + Azm treatment in the dgt genotype reduced the plant diameter compared to the control. BS and BS + Azw reduced the number of roots in the Micro-Tom. The results strongly support that the mixture of B. subtilis and A. brasilense can reduce some parameters of plant development; however, this effect is possibly an interference in the mode of action of growth promotion of each isolate and is not related to an excess of IAA produced by the bacteria.

Swine wastewater compost and arbuscular mycorrhizal fungi in the growth and accumulation of copper in Eucalyptus grandis

The objective of this work was to determine the influence of arbuscular mycorrhizal fungi (AMF) and swine wastewater compost (SWC) on the growth and accumulation of copper in Eucalyptus grandis cultivated in soil contaminated with copper. The experiment was conducted in a greenhouse for 120 days, using a completely randomized experimental design in a factorial arrangement (2 × 3), with and without 40% SWC (v: v) and three inoculation treatments with AMF (without fungus, Gigaspora margarita and Aucalospora colombiana), totaling six treatments with eight replicates in soil previously contaminated with 400 mg kg−1 of copper. The height, stem diameter, root and shoot dry mass, and root and shoot content, Dickson quality index and translocation, relative efficiency of treatments for height of the seedlings and mycorrhizal colonization were evaluated. The addition of SWC and Gigaspora margarita increased morphological parameters and quality of seedlings in contaminated soil.

ROOT parameters of sugarcane and soil compaction indicators under deep strip tillage and conventional tillage

Soil tillage and agricultural traffic generate changes in soil physical attributes and affect the growth of the roots. This study evaluates the impact of system soil tillage on compaction and sugarcane root growth. The experiment was carried out on a Rhodic Kandiudox with two soil tillages (Deep Strip Tillage and Conventional Tillage) and two positions (beds or traffic lane and no traffic lane), totaling four treatments (DST-beds + no traffic lane, DST-traffic lane, CT-no traffic lane and CT-traffic lane). Soil penetration resistance (SPR), bulk density, dry mass, and root system lengths and volumes were evaluated. DST-beds presented lower values for SPR (1.45 MPa) compared to the other treatments (2.55 MPa). This lower SPR did not reflect significant increases in root growth in relation to the DST-traffic lane, meaning that the roots were not confined to the beds. The dry root mass for CT- traffic lane was 35% less than for DST- traffic lane, and CT-no traffic lane reduced of the root dry mass in the layers 0.0–0.2 and 0.2–0.4 m by 62% and 47%, respectively, compared to the DST-beds. Therefore, CT, although widely used, does not create adequate conditions for root development in the first sugarcane cycle, even in lanes with no traffic.

Sustainable organic substrate production using millicompost in combination with different plant residues for the cultivation of Passiflora edulis seedlings

The use of sustainable organic substrates of recognized quality is essential in the production of seedlings of fruit species. In this context, the present study aimed to formulate different sustainable organic substrates based on millicompost combined with different proportions of locally available organic waste, such as coconut fiber ( Cocos nucifera ) powder, gliricidia ( Gliricidia sepium) and elephant grass shavings ( Pennisetum purpureum) for the production of Passiflora edulis seedlings. The organic substrates used were as follows: S1- millicompost; S2- commercial substrate and substrates formulated based on millicompost: S3%–25% millicompost + 25% gliricidia + 25% elephant grass + 25% coconut fiber; S4%–50% millicompost+ 50% elephant grass; (S5) 50% millicompost+ 50% gliricidia; (S6) 50% millicompost+ 50% coconut fiber. At 56 days of sowing, the following morphological parameters were evaluated: shoot dry mass (SDM); root dry mass (RDM); plant height (PH); number of leaves (NL); stalk diameter (SD); root volume (RV); leaf area in cm 2 (LA); seedling vigor (SV) and clod stability (CS). The nutrient contents (N, P, K, Ca and Mg) accumulated in the shoot dry mass of the seedlings were determined after this period. The organic substrates that provided seedlings with significantly higher parameters (P <0.05) of SDM, RDM, PH, NL, SD, RV, LA, SV and CS were as follows: S1> S6> S5. The other substrates (S2, S3 and S4) presented seedlings with morphological parameters similar to each other. In addition, there was a greater accumulation of P, K Ca and Mg (P <0.05) in the shoot dry mass of the seedlings developed on the substrates S1> S6> S5. The substrates S6 and S5 represent two new options of sustainable substrates, being effective in the production of yellow passion fruit seedlings with excellent vegetative growth rates. • Millipedes are able to transform agricultural and urban waste into organic compost. • The use of millicompost in the cultivation of Passiflora edulis seedlings was evaluated for the first time. • The millicompost is efficient and has produced healthy and vigorous seedlings. • Organic substrates based on millicompost with powdered coconut fiber or gliricidia are efficient. • New organic substrate options for passion fruit seedling producers are available.

Production and morphophysiological responses of Panicum maximum cv. BRS Zuri to water availability

Due to the increasing intensification of livestock farming and agricultural systems, there is demand for highly productive forage species. Panicum maximum cv. BRS Zuri is forage that has good productivity, vigor and promotes good animal performance. The objective of this study was to evaluate the morphophysiological and production characteristics of Panicum maximum cv. BRS Zuri subjected to water availability in Fluvic Neosol (Entisol). A potted-plant experiment was conducted in a greenhouse at the Federal University of Rondonópolis, Brazil. The experimental design was completely randomized, with five levels of water availability, corresponding to 25, 50, 75, 100 and 125 % of the maximum soil water holding capacity, and six replicates, in three successive cuts. The variables analyzed were: soil pH, SPAD index, plant height, leaf area, shoot dry mass, root dry mass, root volume, water consumption and water use efficiency. Water availability influenced the development of Panicum maximum cv. BRS Zuri, with the highest results between 67 % and 111 % of the maximum soil water holding capacity. The results show that the production and morphological responses were negatively influenced by water availability levels of 25 % and 125 %. These results makes it possible to affirm that, under the studied conditions, the cultivar BRS Zuri showed moderate adaptation to 125% water availability (excess water).

Soybean growth and production under straw of maize, Urochloa brizantha, Conyza spp. and Digitaria insularis

Weeds can cause serious damage during soybean development, due to allelopathy, competition for water, light and nutrients. It is necessary to investigate the influence of straw, of weeds Conyza spp. and Digitaria insularis, in soybean growth, production and composition and grains. If there is influence of allelopathic compounds at the crop. The aim of this study was to evaluate the influence of straw of maize and Urochloa brizantha (A.Rich.) R.D.Webster crops and Conyza spp., D. insularis, on growth, production and composition of grains produced by soybean. Treatments consisted of the control (absence of straw), maize straw, Urochloa brizantha straw, Conyza spp. straw (500, 1000, 1500 or 2000 kg ha-1) and D. insularis straw (500, 1000, 1500 or 2000 kg ha-1). The chlorophyll index, height of plants and insertion of the first pod, stem diameter at the collar and at 5 cm from the collar, root dry mass, number of pods and grains, weight of total grains, weight of 100 grains, protein and nitrogen (N), catalase and peroxidase contents in grains were evaluated. There was no difference between treatments for plant height, first pod height and chlorophyll index, as well as for total pods and 100 grain weight and protein content, N content and peroxidase and carboxylase enzymatic activity of the grains produced. For stem diameter, a higher value was found for the treatment with maize straw compared to the control (no straw). For dry root matter, treatments without straw and with Conyza spp. straw up to 1500 kg ha-1, differed from the treatment with maize straw. Even in some respects they provided beneficial effects compared to the absence of straw, which indicates the importance of crop residues. No allelopathic effects of weeds were observed on the growth and development of soybean. Conyza spp., D. insularis, maize or U. brizantha straws do not negatively affect soybean growth, production and grain composition.

Piruvato de cálcio como mitigador do estresse salino em mudas de maracujazeiro amarelo

ABSTRACT Although the semi-arid region of Northeast Brazil is a major producer of yellow passion fruit, the problems of salts in the soil and water sources, in many areas have limited the growth and production of this crop, which highlights the importance of studies aimed at reducing such effects. In this context, the objective of this study was to evaluate the effect of foliar application of pyruvate, as a mitigator of salt stress, on the morphophysiology of yellow passion fruit, in seedling phase. The treatments consisted of three electrical conductivities of irrigation water (ECw: 0.8, 2.4, and 4.0 dS m-1) and three concentrations of pyruvate (0, 25, and 50 mM), distributed in a randomized block experimental design in a 3 × 3 factorial scheme, with four replications and two plants per plot. Irrigation with ECw of 4.0 dS m-1 reduces growth variables, phytomass, Dickson quality index, and increases electrolyte leakage in passion fruit seedlings cv. Redondo Amarelo. Exogenous application of calcium pyruvate (25 and 50 mM) increased growth, phytomass, Dickson quality index, relative water content and leaf succulence and reduced electrolyte leakage in the leaf blade in passion fruit. Exogenous application of pyruvate attenuates salt stress, with beneficial effects on CO2 assimilation rate, transpiration, instantaneous carboxylation efficiency, intrinsic water use efficiency, and root dry mass.

Growth regulation by air stream-based mechanical stimulation in tomato (Solanum lycopersicum L.) – Part II: Phenotypic and physiological responses

Plant responses to mechanical stimulation have a great potential for growth control of ornamentals plants and vegetable seedlings and is a major requirement to ensure plant compactness and stability. 21 days old tomato (Solanum lycopersicum cv. ‘Romello’) plants were exposed to regularly applied mechanical stimuli for 14 days by applying of a defined air stream through a custom-built air stream applicator. Air stream application gradually reduced total plant leaf area by 14% and promoted radial growth relative to internode length compared to the untreated control, resulting in a more compact and stable plant phenotype, which was also related to an increased stem dry matter content of the air stream-treated plants. The reduction in total plant leaf area was compensated for the translocation of proportionally more assimilates to light-harvesting tissues and to stems at the expense of dry mass accumulation in petioles. Total stem, leaf and root dry mass of air stream-treated plants were unaffected. The specific leaf area of the air stream treated plants was reduced compared to the control, resulting in an increased relative leaf greenness and consequently in an 8% higher net carbon assimilation rates on average compared to the control. Thereby, air stream-treated plants were able to maintain overall biomass accumulation at the same level as the control. Leaf transpiration rate of air stream treated plants was not markedly affected in the long-term. The technique presented should be easily transferable to other plants, such as ornamentals where the application of chemical plant growth regulators is still the most common technique for plant growth control.

Air temperature during cutting propagation of cold-intermediate and -sensitive crops can be reduced if root-zone heating is provided

Asexual propagation of herbaceous ornamentals occurs from late winter to early spring coincides with seasonally low daily light integrals (DLIs) and average daily temperatures (ADT) outdoors. Supplemental lighting and air and root-zone heating (RZH) can be used to promote rapid callus induction and rooting of cuttings. Due to the range of greenhouse crop base temperatures (cold-tolerant, cold-intermediate, and cold-sensitive), one strategy is to reduce the air ADT of certain crops while using RZH as a potential energy saving strategy. Therefore, the objective of this study was to quantify how reduced air ADT and increased RZH temperatures influence root initiation and development of cold-intermediate and-sensitive herbaceous annual and perennial crops propagated by shoot-tip cuttings. Unrooted vegetative cuttings of angelonia ‘Archangel Raspberry’ (Angelonia angustifolia), lantana ‘Landmark Sunrise Rose Improved’ (Lantana camara), New Guinea impatiens ‘Clockwork White Improved’ (Impatiens hawkeri), scaevola ‘Scalora Brilliant’ (Scaevola aemula), thunbergia ‘Sunny Lemon Star’ (Thunbergia alata), verbena ‘Cadet Upright Red’ (Verbena × hybrida), geranium ‘Moxie! Deep Rose’ (Pelargonium interspecific), Kwik Kombos ‘Pink Lemonade Mix’ [petunia ‘Dekko Star Rose’ (Petunia × hybrida), lobelia ‘Techno Heat Light Blue Improved’ (Lobelia erinus), and calibrachoa ‘Callie Yellow Improved’ (Calibrachoa × hybrida)] and portulaca ‘Cupcake Carrot’ and ‘Colorblast Lemon Twist’ (Portulaca grandiflora) were inserted into a soilless medium and placed in a greenhouse with an air ADT of 21°C and RZH set point of 24°C to callus. After 6 d, trays of cuttings were placed between two greenhouses with an air ADT of 16 or 21°C and among 3 benches which provided RZH set points of 21, 24, or 27°C. After 14 or 16 d post-callus, measurements were collected for all genera and geranium and portulaca ‘Colorblast Lemon Twist’ were transplanted into a common environment. The air ADT and RZH individually influenced stem length of angelonia, lantana, kwik kombos, portulaca, thunbergia, and verbena, and interacted to influence angelonia and lantana. Under an air ADT of 21°C, angelonia was 30%-45% taller than an air ADT of 16°C. Stem length of geranium, New Guinea impatiens, and scaevola were not influenced by air ADT or RZH. With an RZH set point of 21°C, the root dry mass of thunbergia was 72% greater under an air ADT of 21 than 16°C. Lantana shoot dry mass was 23% smaller under an air ADT of 16°C and RZH of 21°C compared to an RZH of 24°C. Finished plants of geranium and portulaca were not influenced by air ADT or RZH and were comparable in size and date of marketability between treatments. Due to little to no differences in crop timing or quality, the majority of the crops studied can be propagated with an air ADT and RZH of 16 and 24°C, respectively, without negative effects during or after propagation.

Crushed amygdaloidal basalt rock and its effects on tomato production

Abstract&#x0D; Sustainable agriculture plays an important role in agricultural productivity, in which it seeks to reduce dependence on conventional synthetic fertilizers (imported from Europe) and promote the use of alternative, low-cost and environmentally friendly sources. An experiment was carried out in the municipality of Santa Maria, Rio Grande do Sul, Brazil, with the objective of evaluating the efficiency and agronomic viability of using a mineral product (amygdaloid basalt powder) as an agricultural input on tomato productivity Solanum lycopersicum. The experimental design used was randomized blocks with six treatments and four replications, at doses 0 (treatment 1 - control), 1.0 ton ha-1 of rock dust (treatment 2), 2.5-ton ha-1 of rock dust (treatment 3), 3.5-ton ha-1 of rock dust (treatment 4), 4.5-ton ha-1 of rock dust (treatment 5), and recommended fertilization for tomato 5-20-20 NPK (treatment 6 - standard). The treatments were applied in December 2018 and the transplant took place in February 2019. According to the conditions under which the experiment was submitted and analyzing the results obtained, it can be inferred that the application of 1-ton ha-1 of amygdaloidal basalt in the soil increased parameters such as root length, stem diameter, green and dry mass of shoots and roots, number of flowers/plants, number of fruits/plant and productivity in tomato Solanum lycopersicum. It is a viable, sustainable, and low-cost strategy that contributes to the achievement of the Sustainable Development Goal (SDG 2) and can be replicated in Brazil and worldwide.