Shoot Matter Research Articles

Arabidopsis thaliana PRR7 Provides Circadian Input to the CCA1 Promoter in Shoots but not Roots.

The core of the plant circadian clock involves multiple interlocking gene expression loops and post-translational controls along with inputs from light and metabolism. The complexity of the interactions is such that few specific functions can be ascribed to single components. In previous work, we reported differences in the operation of the clocks in Arabidopsis shoots and roots, including the effects of mutations of key clock components. Here, we have used luciferase imaging to study prr7 mutants expressing CCA1::LUC and GI::LUC markers. In mature shoots expressing CCA1::LUC, loss of PRR7 radically altered behaviour in light:dark cycles and caused loss of rhythmicity in constant light but had little effect on roots. In contrast, in mature plants expressing GI::LUC, loss of PRR7 had little effect in light:dark cycles but in constant light increased the circadian period in shoots and reduced it in roots. We conclude that most or all of the circadian input to the CCA1 promoter in shoots is mediated by PRR7 and that loss of PRR7 has organ-specific effects. The results emphasise the differences in operation of the shoot and root clocks, and the importance of studying clock mutants in both light:dark cycles and constant light.

Optimum Castor Meal Application in the Cultivation of Pak Choi (Brassica chinensis L.) with Toxicity Survey for Earthworms (Eisenia andrei)

In Taiwan, castor meal (CM) is often used by farmers as an organic fertilizer for the supplement of plant nutrition. It can rapidly increase nitrogen availability for crops. However, the excessive application of CM will affect the ecosystem. This study was conducted to evaluate the optimum concentration of CM that can be used as a fertilizer for balancing crop production and soil ecosystem health (by considering earthworms). Pak choi was selected for the experiment. A randomized block design with three replications was used, with treatments consisting of five concentrations of CM (namely 25, 50, 100, 150, and 200 kg/0.1 ha) and fermented livestock compost 800 kg/0.1 ha, represented as CM25, CM50, CM100, CM150, CM200, and LC800, respectively. The results revealed that soil properties, leaf nutrient concentration, and plant traits, namely plant diameter, plant height, and fresh and dry root and shoot matter, improved with the increasing concentrations of CM, and CM100–CM200, and led to the highest production of pak choi which was equivalent to that with LC800. However, the weight of earthworms decreased as CM concentrations increased. The weight of earthworms was similar between CM25, CM50, CM100, and LC800. In conclusion, given the characteristics of high nitrogen as a fertilizer, the optimal dose of CM was 100–150 kg/0.1 ha for obtaining a balance between crop production and ecosystem safety.

English

The pat gene confers tolerance to glufosinate in transgenic soybean plants; however, some aspects of the selectivity of this herbicide need to be better elucidated. This study aimed to evaluate the development of soybean plants with the pat gene under the application of different glufosinate rates. The experiment was conducted in a greenhouse and included seven different glufosinate rates of and two soybean cultivars (LL0291 and LL0767) with the pat gene, with four replications in a completely randomized design. Glufosinate was applied at the V4 stage (4 nodes on the main stem with fully developed leaves beginning with the unifoliolate nodes) of soybean, and the variables analyzed were: soybean injury, chlorophyll index, plant height, dry and fresh matter of shoots and roots, wet nodules, dry nodules, and total number of nodules. It was found that for both cultivars, the maximum recommended glufosinate rate of 700 g of active ingredient (ai) ha-1 was safe, rates above 1,250 g ai ha-1 may interfere with development, especially biomass accumulation, and, in general, cultivar LL0291 exhibited more injuries than cultivar LL0767. The glufosinate-tolerant soybean (with pat gene) is a great option for farmers, but care should be taken with respect to rates above the maximum recommended in the package insert, so that there is no damage to soybean. © 2021 Friends Science Publishers

ZmACY-1 Antagonistically Regulates Growth and Stress Responses in Nicotiana benthamiana.

Aminoacylase-1 is a zinc-binding enzyme that is important in urea cycling, ammonia scavenging, and oxidative stress responses in animals. Aminoacylase-1 (ACY-1) has been reported to play a role in resistance to pathogen infection in the model plant Nicotiana benthamiana. However, little is known about its function in plant growth and abiotic stress responses. In this study, we cloned and analyzed expression patterns of ZmACY-1 in Zea mays under different conditions. We also functionally characterized ZmACY-1 in N. benthamiana. We found that ZmACY-1 is expressed specifically in mature shoots compared with other tissues. ZmACY-1 is repressed by salt, drought, jasmonic acid, and salicylic acid, but is induced by abscisic acid and ethylene, indicating a potential role in stress responses and plant growth. The overexpression of ZmACY-1 in N. benthamiana promoted growth rate by promoting growth-related genes, such as NbEXPA1 and NbEIN2. At the same time, the overexpression of ZmACY-1 in N. benthamiana reduced tolerance to drought and salt stress. With drought and salt stress, the activity of protective enzymes, such as peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) from micrococcus lysodeikticus was lower; while the content of malondialdehyde (MDA) and relative electrolytic leakage was higher in ZmACY-1 overexpression lines than that in wild-type lines. The results indicate that ZmACY-1 plays an important role in the balance of plant growth and defense and can be used to assist plant breeding under abiotic stress conditions.

Responses of a root system structure to soil compaction stress among maize (Zea mays L.) hybrids

AbstractEffects of soil compaction stress were investigated in maize hybrids subjected to low (L‐1.10), medium (M‐1.30) and high (H‐1.60 g/cm3) soil compaction. The hybrids selected for the study differed in their susceptibility to growth under soil compaction stress conditions. We used appropriate methods of non‐destructive cleaning and analysis of all intact compartments of the root system. Petrolatum–wax test, proved as an effective screening technique for selecting resistant and sensitive maize hybrids, was also employed. The seedlings were grown in custom‐made ‘root‐box’ and ‘root‐basket’ containers. The penetration resistance (PR) strength of 0.52 and 1.07 MPa was satisfactory for estimating root penetration index (RPA) among maize hybrids. The soil compaction stress affected root system structure (RSS) in maize hybrids. The resistant hybrids showed a lower decrease in root dry matter (DM) in M and H treatments at 0.0–15 cm soil depth, and an increase in the number of roots growing at an angle of 0°–30° in relation to the main growth axis, comparing to sensitive hybrids. The soil compaction stress lowered root number (RN) and length (RL), shoot and root DM, and increased shoot to root ratio (S/R). The changes were greater in sensitive than in resistant hybrids. In addition, a regression coefficient (R2) between stress susceptibility index (SSI) and relative trace change (RTC) marked for changes in dry matter of shoot (S), roots (R), shoot to root (S/R) ratio and root length (RL) and number RN was statistically significant. Seedlings of maize single‐cross hybrids demonstrated differences in their responses to soil compaction stress, which caused changes in shoot and root dry matter and the distribution of roots in the soil profile.

Use of growth regulator in reducing the size of Sesbania punicea (Cav.) Benth.

Sesbania punicea (Cav.) Benth. is a species with ornamental potential, highlighted by the orange color of the flowers and the formation of inflorescences in racemes. Because it is a native species and few plant breeding information, studies are needed to be used commercially, one of the aspects to be investigated is the reduction of its size for potting. The objective was to evaluate the influence of daminozide in reducing the size of Sesbania punicea. The seedlings were grown in 2.8 L pots containing substrate based on pine bark. A completely randomized design was used, with 3 treatments, 1 control, with 4 replications, 5 plants per plot. The treatments consisted of daminozide in doses of 2, 4 and 6 g L⁻¹ and control (water + 1 mL L⁻¹ adhesive spreader) that were sprayed using a 2 L accumulated pressure sprayer on the plants on the 22nd and 44th days after transplant. At the end of the experiment, height, stem diameter, dry matter of shoot and roots, chlorophyll a, b and total, number of leaves and internodes were evaluated. There were significant differences for plant height, stem diameter, number of leaves per plant and shoot dry matter. It is concluded that the dose of 5.8 g L⁻¹ of daminozide showed superior results for the reduction the size of this species.

The influence of photoselective shade netting on vegetative growth and bioactivity of Myrsine africana L. for cosmeceutical production

As the global desire for natural remedies derived from botanicals increases, the pressure on plant populations and biodiversity intensifies. Therefore, to conserve biodiversity as a valuable genetic and biochemical resource, sustainable utilisation and commercial production should be prioritised. Myrsine africana L. (MA), has recently been found to possess significant cosmeceutical properties, such as elastase inhibition (anti-wrinkle) and anti-tyrosinase (skin even tone) activity. However, this species is relatively slow growing, recalcitrant to adventitious root (AR) development, and has slightly insufficient bioactivity in raw extracts. These factors reduce the economic feasibility of producing this commercially valuable indigenous species. Consequently, this may enhance wild harvesting of this species, placing pressure on wild populations. Manipulation of light is a common practice in plant production to exploit plant growth and development, as light quantity and quality effectively influence the primary and secondary metabolism of plants. Therefore, the current study aimed to investigate the influence of selected photoselective shade net on vegetative growth and metabolites of MA shoot material. Results displayed significantly enhanced growth (p < 0.001) under green (50 % density), black (50 %) and red (80 %) shade net in comparison to the control (cultivation under full sun) and inhibited growth under blue (50 %) shade net. Shade net effectively influenced starch and soluble carbohydrate content. Furthermore, significantly higher elastase inhibition was observed under green and red shade net treatments in comparison to the control in autumn, with IC50 values of 18.59 μg/mL, 19.28 μg/mL and 37.93 μg/mL, respectively. In addition, bioactivity was significantly higher in autumn (p < 0.001) under green, red and control treatments. It can be concluded that photoselective shade net may be used to enhance plant growth and bioactivity of MA.

Optimizing the Biosorption Behavior of Ludwigia stolonifera in the Removal of Lead and Chromium Metal Ions from Synthetic Wastewater

In this study, a natural low-coast, efficient, and eco- bio-sorbent plant material (Ludwigia stolonifera), with both parts of the root and shoot, were studied for the removal of the cationic metal ions, lead Pb2+ and chromium Cr6+, via batch mode experiments to evaluate their maximum adsorption capacity, and held a comparison between the used bio-sorbent roots and shoots, based on the highest bio-sorption potential. Optimization of the bio-sorption parameters, such as contact time, pH, bio-sorbent (root and shoot) dosage, and initial ion concentration was conducted. The results indicated that 1.6 g of the used bio-sorbent shoot material removed 81.4% of Pb2+, and 77% of Cr6+ metal ions from liquid media under the conditions of 100 ppm of initial metal ions concentration at room temperature for 60 min of contact time with the static condition. Different isotherms and kinetic models were fit to the experimental data to understand the nature of the bio-sorption process. The experimental data were best fit by the pseudo-second-order kinetic model with a high correlation coefficient (R2 = 0.999), which reveals the chemisorption nature of the bio-sorption process. The chemical and structural analysis of the used bio-sorbent, before and after Cr6+ and Pb2+ bio-sorption, were performed using different techniques of characterization, such as Scanning Electron Microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The used bio-sorbent proved to be a low-cost, efficient, and eco-friendly material to remove heavy metal ions from aqueous solutions.

PERFORMANCE OF LETTUCE SUBMITTED TO THE ROCK DUST REMINERALIZER AND DOSES OF EFFICIENT MICROORGANISMS

The use of soil remineralizers with efficient microorganisms (EM) can represent an effective and sustainable alternative to improve the growth, development, and yield of cultivated plants. Thus, the present study aimed to evaluate the effect of different doses of EM, in the presence or absence of rock dust (RD), on the development of iceberg lettuce, cultivar Lucy Brown. The design used was completely randomized, arranged in a 2 x 5 factorial scheme, with four replications. The treatments consisted of the presence and absence of RD in the substrate composition, combined with five commercial product doses based on EM (0, 2, 4, 6, and 8 L ha-1). At 30 days after transplanting, root and stem length, head circumference, the number of leaves, stem diameter, leaf area, fresh matter of root, stem, leaf, and shoot, and dry matter of root, stem, leaf, and shoot were evaluated. There was an interaction between the factors for most variables of economic importance. The dose of 4.5 L ha-1 of the product based on EM, combined with PR, implied the best performance of iceberg lettuce under the studied cultivation conditions.

Modified BBCH codification and correlation of phenological characteristics with climatic variables in jamun (Syzigium cuminii Skeels)

Jamun (Syzigium cuminii Skeels) is gradually gaining importance due to its extraordinary medicinal properties and enhanced demand for fresh fruit, which is buttressed by the growth of the processing industry. Curative property of Jamun fruits against Diabetes mellitus type 2 has boosted its commercial orcharding, which necessitates gathering precise information on phenological responses to changing temperature and precipitation. A modified three digit extended Biologische Bundesanstalt Bundessortenamt and Chemische Industrie (BBCH) scale was developed and assigned 3 digit codes to describe the important phenological stages. Eight principal growth stages and 36 secondary stages have been described with illustrations that occur sequentially in Jamun under subtropics. Interestingly the primary phenophases of vegetative phenology i.e. bud development, leaf development and shoot development showed a large overlap and the interrupted phenostages are attributed to the inclemental weather conditions. Thus, under a warm temperate subtropical climate in the northern hemisphere, Jamun canopies presented two vegetative flushes (represented as mesostage 1 and 2), the second flush registering highest frequency (60–80 %) in months of September to October. This is in contrast to continuous growth under tropical climate conditions, wherein growth cessation does not occur. While vegetative growth flush occurred twice a year in a major part of canopy, flower-bearing panicles emerged on mature shoots in the months of February and March. Floral induction characterized by the inflorescence emergence and subsequent blooming closely followed the upswing of average monthly minimum and maximum temperature curve under subtropics, while average temperature downturn coupled with high precipitation released the vegetative flush episode. The phenostage (5) involving inflorescence emergence and growth occurred once in the subtropical climate, sustaining for around 8 weeks, followed by flowering (6) and fruit development(7). As with other evergreen trees, vegetative growth did not depict cessation and dormancy was observed after harvest and onset of winter. The correlation of emerging phenological events with temperature and humidity established the utility of the BBCH code for forecasting the outcomes of the canopy shoots. Early fruit production and synchronous shoot growth can be targeted by imposing shoot pruning strategy immediately after harvest at dormancy. The study establishes interplay of ecogeography and germplasm for expression of standard phenostages and the impact of climate change on fruit productivity.

Mapping Phragmites cover using WorldView 2/3 and Sentinel 2 images at Lake Erie Wetlands, Canada

Phragmites australis (Cav.) Trin. ex Steudel subspecies australis is an aggressive plant invader in North American wetlands. Remote sensing provides cost-effective methods to track its spread given its widespread distribution. We classified Phragmites in three Lake Erie wetlands (two in Long Point Wetland Complex (LP) and one in Rondeau Bay Marsh (RBM)), using commercial, high-resolution (WorldView2/3: WV2 for RBM, WV3 for LP) and free, moderate-resolution (Sentinel 2; S2) satellite images. For image classification, we used mixture-tuned match filtering (MTMF) and then either maximum likelihood (ML) or support vector machines (SVM) classification methods. Using WV2/3 images with ML classification, we obtained higher overall accuracy for both LP sites (93.1%) compared with the RBM site (86.4%); both Phragmites users’ and producers’ accuracies were also higher for LP (89.3% and 92.7%, respectively) compared with RBM (84.3% and 88.4%, respectively). S2 images with SVM classification provided similar overall accuracies for LP (74.7%) and for the RBM (74.3%); Phragmites users’ and producers’ accuracies for LP were 85.3% and 76.3%, and for the RBM, 69.1% and 79.2%, respectively. Using WV2/3, we could quantify small patches (percentage cover ≥ 20%; shoots ≥ 1 m tall; stem counts > 25) with accuracy > 80%, whereas parallel effort with S2 images only accurately quantified high density (> 60% cover), mature shoots (> 1 m tall; Stem counts > 100). By simultaneously mapping young or sparsely distributed Phragmites shoots and dense mature stands accurately, we show our approach can be used for routine mapping and regular updating purposes, especially for post-treatment effectiveness monitoring.

ДИНАМИКА РАЗВИТИЯ ПОБЕГОВ КУСТАРНИКОВЫХ ИВ (SALIX, SALICACEAE)

The article presents the results of observations of the seasonal dynamics of the growth of annual shoots of two species of shrub willows: Salix triandra and Salix viminalis. Object: genetically aligned model inbred-clonal populations of S. triandra and S. viminalis. Material: growing shoots on annual cuttings. Methods: comparative morphogenetic, chronobiological, numerical analysis of the series of dynamics. Results. Clones of two species of shrub willows, phylogenetically distant from each other, demonstrated high productivity along the length of shoots on annual cuttings. On the shoots of the strongest clone of S. triandra, the length of mature shoots was 176–215 cm, on the shoots of the strongest clone of S. viminalis - 132–192 cm. As the shoots grow, the differences in length between them increase. No significant influence of the clone factor on the dynamics of the daily growth of S. triandra shoots was revealed, and the effect of the clone factor on the dynamics of the daily growth of S. viminalis shoots is insignificant. In the seasonal dynamics of the daily growth of shoots, regardless of their species and clonal affiliation, three stages of shoot development were identified: spring, early summer, and late summer. The transitions between stages are synchronized in clones regardless of species. Qualitative interspecific and interclonal differences in the seasonal dynamics of daily shoot growth were not revealed. Quantitative interspecific differences in the seasonal dynamics of daily increment were revealed only at the second stage of shoot development, with high values of daily increment. Significant interclonal differences in the seasonal dynamics of daily growth were not found: differences between the trajectories of shoot development are due to intraclonal variability within each species. Recommendations. When planning, creating and operating pure and mixed cultures of S. triandra and S. viminalis, take into account the fundamental similarity in the seasonal dynamics of the development of shoots of different species of shrub willows. When harvesting and planting cuttings, use a homogeneous mother material. Culling of weak cuttings that are lagging behind in development should be carried out in the first year of life.

Influence of Arbuscular Mycorrhizae on the Development and Attack of Leaf-Cutting Ants in Clonal Seedlings of Eucalyptus urophylla x Eucalyptus camaldulensis

The present study aimed to evaluate the effect of the mycorrhizal association in the development and attack of leaf-cutting ants Atta sexdens (Linnaeus, 1758) in clonal seedlings of Eucalyptus urophylla x Eucalyptus camaldulensis hybrid. The treatments consisted of inoculated and uninoculated seedlings with 100 grams of sand containing spores from arbuscular mycorrhizal fungi (AMF) collected on native soil from four different areas of the amazon: native forest area (NF), permanent preservation area recovered to three years (PPA03), permanent preserved area degraded (PPAD) and permanent preservation area recovered to four years (PPA04). At 45 and 90 days after inoculation (d.a.i.), height, fresh and dry matter of shoot and root, root development, number of leaves, stem diameter and tolerance to leaf-cutting ants were evaluated. In the first group of plants (45 d.a.i.), mycorrhizal plants presented the higher root volume with the use of APP04, APP03 and NF all with 6.16 mm. For the second group of plants (90 d.a.i.), the highest root volume was also found on mycorrhizal plants with the soil of APP03 and control with 7.16 mm. For the attractiveness test of ants, 16 discs were taken from the non-inoculated seedlings. Regarding the disks of mycorrhizal seedlings with the soil of APP04, only 9 were taken. Although the use of AMF to stimulate plant resistance to attack by leaf-cutting ants is a new study, studies related to the influence of mychorrizas on plant development are quite common and the results presented in this study did not evidence the influence of mychorrizas on plant development. However, it was observed that the early inoculation of the seedlings can reduce the attractiveness of leaf-cutting ants by the seedlings of the hybrid Eucalyptus urophylla x Eucalyptus camaldulensis, already in the first 45 d.a.i of the seedlings and the inoculum used can interfere in this process.

Temperature Regimes on Seeds Germination and Growth Parameters of Wheat (Triticum aestivum L.) Genotypes at Early Seedling Stage

&#x0D; To observe the effect of high temperatures stresses i.e., normal (25 °C), high (30 °C) and very high (35 °C) stress, on germination and seedling growth on wheat genotypes a water culture study was conducted under controlled conditions (growth incubators). Eighteen newly developed wheat lines (DH- I, DH-3, DH-4, DH-5, DH-6, DH-7, DH-8, DH-10, DH-11, DH-12, DH-13, DH-14, DH-15, DH-16, DH-18, DH-19, DH-20 and DH-21) were tested along with two local checks i.e., Kiran-95 and LU-26s. There was a gradual reduction in germination and seedling growth at 30 °C and 35 °C. Among the tested genotypes the genotype DH-16 showed least reduction i.e. only 2.27% reduction in germination at 35 °C. On the other hand the genotype DH-6 showed maximum reduction (28.09%) at 35 °C. High temperature stresses also affected on other growth parameters i.e. shoot and root length (cm), fresh and dry matter (g) of shoot and root and the moisture contents. It is based on relative reduction over control in various growth parameters at very high temperature stress (35 °C), four genotypes viz., DH-3, DH-5, DH-8 and DH-13 appeared as tolerant, nine genotypes i.e., DH-1, DH-4, DH-7, DH-10, DH-11, DH-14, DH-18, and LU-26s appeared as medium tolerant and two as medium sensitive i.e. DH-6 and DH-16. On the other hand six genotypes viz., DH-12, DH-15, DH-19, DH-20, DH-21 and Kiran-95 showed sensitivity 35 °C over 25 °C. It is therefore concluded that the genotypes DH-3, DH-5 and DH-13 can be cultivated on heat prone areas of Pakistan especially in Sindh province.&#x0D; &#x0D;

Growth of canola hybrids resistant and sensitive to herbicides

Plant growth analysis is useful for determining adequate management practices and exploring the maximum yield potential of cultivars or hybrids. Canola hybrids with resistance to herbicides have been studied and registered for Brazilian conditions, as they improve weed management in canola crops. This study evaluated the growth of canola hybrids resistant to triazine or imidazolinone herbicides compared to a sensitive hybrid. The experiment was conducted using a completely randomized design, with four replications, in a bifactorial scheme using three hybrids and six sampling times. The canola hybrids used were Hyola 571CL (resistant to imidazolinones), Hyola 555TT (resistant to triazines), and Hyola 61 (sensitive to both herbicides). Height, leaf area, and dry matter of roots, leaves, stems, and shoots of the plants were evaluated at 14, 28, 42, 56, 70, and 119 days after emergence (DAE). The physiological indices absolute growth rate, leaf area ratio, specific leaf area, and net assimilation rate were calculated, and yield indices evaluated. Compared to Hyola 61, the Hyola 555TT hybrid showed lower values of leaf dry matter at 70 DAE, absolute growth rate up to 56 DAE, and net assimilation rate at 14 and 28 DAE, and a higher leaf area ratio at 56 DAE, whereas the hybrid Hyola 571CL presented lower leaf area and lower leaf dry matter at 70 DAE. At flowering, compared to Hyola 61, the hybrid Hyola 571CL presents lower leaf area, and the hybrids Hyola 555TT and Hyola 571CL have lower leaf dry matter accumulation. Differences in the growth of canola hybrids Hyola 555TT, Hyola 571CL and Hyola 61 do not cause differences in their grain yield.

Management of gummosis in citrus with potassium phosphite

This work aimed to evaluate the potassium phosphite-based commercial product, Phytogard®, as a complementary tool for the management of gummosis in citrus. Seedlings of tangerine ‘Sunki’ were sprayed at concentrations 0; 0.5; 2 and 5 mL L-1 of Phytogard® and subsequently inoculated with zoospores of Phytophthora nicotianae. The disease incidence was reduced by 84% in plants sprayed at the concentration 0.5 mL L-1 and the plants sprayed at concentrations of 2 and 5 mL L-1 showed zero disease incidence. There was increased an production of fresh matter of shoot and roots in plants sprayed and inoculated with the pathogen compared to unsprayed plants. Plants sprayed with Phytogard® and inoculated with the pathogen showed lower values for total phenols, enzyme activity for phenylalanine ammonia-lyase and peroxidase and for total protein content in root tissues compared to non-inoculated plants. There was higher activity of the enzyme β 1.3-glucanase in root tissues of plants inoculated with the pathogen that received the product at the concentration of 2 mL L-1. The results of this study showed that the potassium phosphite-based product Phytogard® has potential for the control of Phytophthora nicotianae in seedlings of tangerine ‘Sunki’. However, it is not possible to conclude that this control occurs through resistance induction.

Control of Stretching of Tomato (Lycopersicon esculentum Mill.) on Cylindrical Paper Pot Seedling Using High-Salinity Potassium Fertilizers

This study was conducted to examine the potential of inducing salinity stress on cylindrical paper pot tomato seedlings to inhibit overgrowth. Potassium fertilizers, sulfate of potash (K2SO4), muriate of potash (KCl), and monopotassium phosphate (KH2PO4), were prepared as two solutions of (5 and 10) dS·m-1 salinity level, respectively, to investigate the influence on tomato (Lycopersicon esculentum Mill.) seedling growth. We also investigated the adaptability and survivability of treated tomato seedlings with high-salinity potassium (10 dS·m-1 KCl) to harsh environmental conditions (water deficit, low temperature, and storage conditions). Repeated addition of high-salinity level KCl, K2SO4, or KH2PO4 markedly decreased the dry matter of shoot and root, leaf area, and net assimilate rates (NAR) but increased the stem diameter of seedlings. Among the three sources, the relative growth rate of plant height (RGRH) was most sensitive to KCl addition; increasing salinity levels of KCl solution decreased the RGRH of seedlings. The compactness, which directly reflects the stocky growth index, increased in KCl or KH2PO4 treatments. After a week’s water deficit, severely wilted seedlings were observed in control seedlings (untreated with KCl), but no wilted seedlings were observed in the KCl treated seedlings, and the relative water content (RWC) of the untreated seedlings significantly decreased by 23 %, while that of the pretreated seedlings only decreased by 8 %. The increase in ion leakage of KCl treated seedlings at low temperatures was less than that of untreated seedlings. Furthermore, there was far lower damage proportion on pretreated seedlings at (9, 12, and 15)°C storage temperatures after 20 days, compared with on unpretreated seedlings. Our results suggest that high-salinity potassium fertilizer, especially KCl, is effective in preventing tomato seedling overgrowth, while it also improves tolerance.

Pó de basalto como fertilizante alternativo na cultura do feijão preto em Latossolo vermelho

O pó de basalto (PB) vem sendo utilizado como fonte de nutrientes alternativo em algumas culturas no Brasil, sobretudo em graníferas, como o feijão preto. Desse modo, o objetivo do estudo foi avaliar o efeito de doses de PB na produção de matéria seca da parte aérea (MSPA) e grãos de feijão preto em Latossolo vermelho. O experimento foi conduzido por dois anos experimentais, safras 2017/18 e 2018/19 em delineamento de blocos casualizados, com três repetições, totalizando 33 parcelas experimentais, constituídas de 6 m² cada. Os tratamentos foram: 5, 10, 20, 40, 60, 80, 120, 160, 200 t ha-1 de PB, além de outro tratamento com fertilização química NPK e uma testemunha - TEST (sem PB e NPK). A semeadura do feijão preto foi com espaçamento de 40 cm entre linhas e 12 cm entre plantas. No estádio de pleno florescimento das plantas foi determinada a produção da MSPA e na colheita, os grãos. A produção de MSPA e grãos de feijão apresentou tendência crescente em relação às doses de PB, ou seja, quanto maior a dose de PB, maior foi a produção de MSPA e grãos, com valores variando de 1091 a 2892 kg ha-1 e 989 a 2111 kg ha-1, respectivamente. Doses de 5 a 60 t ha-1 apresentam ação equivalente na produção MSPA e grãos de feijão preto em comparação com a fertilização química NPK. Doses de PB acima de 80 t ha-1 promovem a maior produção de grãos de feijão preto em Latossolo vermelho.

Root and shoot growth in safflower as affected by soil compaction

Soil compaction, induced by no-tillage practices, can negatively impact soil properties important for plant growth. Compacted soils can restrict root growth depth, resulting in reduced crop yield. Although safflower (Carthamus tinctorius) has a deep root system, yield may still be affected by soil compaction. Therefore, this study aimed to evaluate safflower root and shoot growth when submitted to soil compaction in an Oxisol soil under controlled (greenhouse) and field conditions. Five soil bulk density measures were performed in a greenhouse (1.1, 1.2, 1.3, 1.4 and 1.5 Mg m–3). Four compaction levels (established by the number of passes of a farm tractor: 0, 1, 3, and 5 passes consecutively) were performed to evaluate the effect of soil compaction in the field. Root and shoot growth were measured after harvesting the plants. Safflower root growth was reduced when soil compaction increased from 1.1 to 1.5 Mg m–3 under controlled (greenhouse) conditions. In field conditions, we observed a decrease in root length, and fresh and dry matter in roots and shoots of safflower as the soil compaction increased to 5P (1.28 Mg m–3). The results of our study suggest safflower root and shoot growth can be impacted by soil compaction which could affect crop yield.

Use of Non-Destructive Measurements to Identify Cucurbit Species (Cucurbita maxima and Cucurbita moschata) Tolerant to Waterlogged Conditions.

Limited information is available regarding the physiology of squash plants grown under waterlogging stress. The objectives of this study were to investigate the growth and physiological performances of three cucurbit species, Cucurbita maxima cultivar (cv.) OK-101 (OK) and Cucurbita moschata cv. Early Price (EP) and Strong Man (SM), in response to waterlogging conditions, and to develop a precise, integrated, and quantitative non-destructive measurement of squash genotypes under stress. All tested plants were grown in a growth chamber under optimal irrigation and growth conditions for a month, and the pot plants were then subjected to non-waterlogging (control) and waterlogging treatments for periods of 1, 3, 7, and 13 days (d), followed by a 3-d post-waterlogging recovery period after water drainage. Plants with phenotypes, such as fresh weight (FW), dry weight (DW), and dry matter (DM) of shoots and roots, and various physiological systems, including relative water content (RWC), soil and plant analysis development (SPAD) chlorophyll meter, ratio of variable/maximal fluorescence (Fv/Fm), quantum photosynthetic yield (YII), normalized difference vegetation index (NDVI), and photochemical reflectance index (PRI) values, responded differently to waterlogging stress in accordance with the duration of the stress period and subsequent recovery period. When plants were treated with stress for 13 d, all plants exhibited harmful effects to their leaves compared with the control, but EP squash grew better than SM and OK squashes and exhibited stronger tolerance to waterlogging and showed less injury. Changes in the fresh weight, dry weight, and dry matter of shoots and roots indicated that OK plants suffered more severely than EP plants at the 3-d drainage period. The values of RWC, SPAD, Fv/Fm, YII, NDVI, and PRI in both SM and OK plants remarkably decreased at waterlogging at the 13-d time point compared with controls under identical time periods. However, the increased levels of SPAD, Fv/Fm, YII, NDVI, and PRI observed on 7 d or 13 d of waterlogging afforded the EP plant leaf with improved waterlogged tolerance. Significant and positive correlations were observed among NDVI and PRI with SPAD, Fv/Fm, and YII, indicating that these photosynthetic indices can be useful for developing non-destructive estimations of chlorophyll content in squashes when screening for waterlogging-tolerant plants, for establishing development practices for their cultivation in fields, and for enhanced cultivation during waterlogging in frequently flooded areas.