Nest refuse of Acromyrmex balzani (Hymenoptera: Formicidae) increases the plant vigor in Turnera subulata (Turneraceae)

Some studies report the positive effect of organic residues from ant nests on soil properties and on the structure of the adjacent plant community in field experiments, but there is a gap about the effect on individual species. The purpose of the present study was to compare the soil nutrient content and the development of Turnera subulata Smith, an ornamental species, in the presence of the nest refuse (basically composed of fragments of grass leaves and the symbiotic fungus) produced by the leaf-cutting ant Acromyrmex balzani (Emery, 1890) or in control soil through a greenhouse pot experiment. The experiment was carried out with two treatments: control soil and soil with 25% of nest refuse. The plants were kept in 1L pots for 90 days. We evaluated the parameters: plant height, stem diameter, root length, number of leaves, dry weight of the root, dry and fresh aboveground biomass. Additionally, the relative chlorophyll content and leaf nutrients were used as nutritional parameters. As a result, plants that grew in the soil with nest refuse showed significant higher values of all parameters evaluated when compared to the control treatment (p < 0.001). We conclude that this biofertilizer contributed to the production of more vigorous plants, being able to act on the local dynamics of nutrients in the ecosystems where A. balzani occurs. As it is relatively abundant and easy to collect, the refuse of A. balzani has the potential to be used as an alternative substrate in the production of shortlife cycle plants.

Growth, nutrient accumulation and yield of onion as a function of micronutrient fertilization

ABSTRACT Micronutrients structurally constitute several enzymes and act as a cofactor of essential proteins to maintain cell function, thereby contributing to crop growth and yield. The objective of this study was to evaluate the leaf content, growth, accumulation of micronutrients, classification and yield of onion as a function of fertilization with boron, cooper and zinc in two years of cultivation. The experiments were carried out from June to November in 2018 and 2019, in a soil classified as Ultisol, both at the Rafael Fernandes Experimental Farm, belonging to the Universidade Federal Rural do Semiárido, in the municipality of Mossoró, Rio Grande do Norte, Brazil. The experimental design was in randomized blocks with 15 treatments and four replicates. The treatments consisted of application of doses of B, Cu and Zn, in two experiments. Contents of B, Cu and Zn in the diagnostic leaf, growth, accumulation of B, Cu and Zn in the leaf, bulb and total, classification and commercial, non-commercial and total yields were evaluated. Application of B, Cu and Zn did not influence the number of leaves, relation of bulb shape, leaf, bulb, and total dry mass and yield of onion. Application of B, Cu and Zn, respectively at doses of 1-2-1 kg ha-1 favored a greater accumulation of B, Zn and Cu in the bulb. Higher number of leaves, leaf dry mass, bulb dry mass, total dry mass, class 1 bulbs and non-commercial yield were produced in Experiment 1.

Morphological variation of iron toxicity tolerance in lowland rice (Oryza sativa L.) varieties

Rice (Oryza sativa L.) is a staple food crop in many countries in Africa. Africa consumes 11.6 million tons of rice per annum and out of 39 rice-producing countries, 21 import 50% to 99% of their rice requirements. The inability to reach the yield potential that would sustain Africa’s need for rice is due to many biotic and abiotic constraints that rice production faces. In lowland grown rice, one of the abiotic factors hindering rice production is iron toxicity. Excess uptake of ferrous (Fe2+) ions leads to a physiological stress, which results, into poor production. The current study aimed at selection of varieties tolerant to iron toxicity and assessment of the genetic diversity linked to this trait. In a hydroponic experiment conducted in a screen house at Africa Rice Centre in Dar es Salaam, 32 rice varieties were evaluated for tolerance to iron toxicity. The experiment was laid out in a split plot design with iron concentration as the main plot factor and variety as the sub plot factor. Two levels of iron concentration were used: 2 ppm and 300 ppm of Fe2+ as control and test concentrations, respectively. Traits observed to gauge tolerance were leaf bronzing (an indicator of iron toxicity), plant height, tillering, number of leaves, shoot weight (above ground), root length and root weight. The varieties ARICA8, and CK801 were found to be tolerant due to low bronzing indices, higher shoot weight, more number of leaves and lack of significant variation in morphology between the two Fe treatments except for the plant height. Correlation analysis depicted negative correlation between leaf bronzing and the other traits measured especially shoot biomass.

Physiological responses of Triplaris gardneriana Wedd. seedlings (Polygonaceae) under intermittent drought

Triplaris gardneriana Wedd is a deciduous riparian tree occurring in areas with different climatic conditions in Brazil, from the rainforest to the tropical dry forest. An increase in global temperature and drought events can change the growth pattern and establishment of the species. To evaluate the effects of intermittent drought on the growth of T. gardneriana seedlings, an experiment was performed using seedlings with one month old subjected to three water treatments (daily irrigation as control, and intermittent drought through cycles of water suppression of seven (S7) and 14 days-intervals (S14) between watering. Growth, biomass production and partitioning, relative water content (RWC), the accumulation of organic solutes, protoplasmic integrity and phenotypic plasticity index (PPI) were evaluated for a better understanding about its drought tolerance level. Intermittent drought severely affected plants growth in S14 plants, showing lower plant height, number of leaves, leaf area, and dry biomass. RWC was reduced, while carbohydrates and proline contents increased in response to drought stress. Protoplasmic damage increased electrolyte leakage in plants subjected to severe stress. However, T. garderiana demonstrated moderate tolerance to water deficit. The plastic changes observed were more physiological than morphological. Therefore, T. gardneriana seems to be a moderately tolerant species to intermittent drought.

PENGARUH KOMBINASI IAA (Indole-3-Acetic Acid) DAN BAP (6-Benzylaminopurine) TERHADAP INISIASI TANAMAN VANILI (Vanilla planifolia Andrews)

Provision of Vanilla (Vanilla planifolia Andrews) with traditional cultivation often has problems, including the availability of unhealthy seeds due to disease caused by Fusarium oxysporum. This disease can thwart vanilla plantations up to 85% because the pathogen can infect all parts of the vanilla plant making it difficult to control efforts. Alternative efforts were made to overcome this problem, namely through the initiation process in tissue culture by combining the hormones IAA (indole-3-acetic acid) and BAP (6-benzylaminopurine). This study aims to determine the effect and the maximum concentration of the combination of IAA and BAP on the initiation of vanilla plants. This study was conducted based on a completely randomized design (CRD) with 5 treatments and 3 repetitions. This treatment consisted of: A (MS + 0.1 ppm IAA + 1 ppm BAP), B (MS + 0.2 ppm IAA + 1 ppm BAP), C (MS + 0.3 ppm IAA + 1 ppm BAP), D (MS + 0.4 ppm IAA + 1 ppm BAP), and E (MS + 0.5 ppm IAA + 1 ppm BAP). Observations were made after 40 days from the planting process. The results showed that the concentration of the combination of IAA and BAP can affect the growth and organogenesis of the initiation of vanilla plants (Vanilla planifolia Andrews). Treatment C (MS + 0.3 ppm IAA + 1 ppm BAP) was the best concentration from this study, with average values: number of shoots (1), shoot length (1.73 cm), number of roots (1), and number of leaves (1.33).

Russian and Foreign Cultivars of Honeysuckle (Lonicera edulis Turcz.): cultivation studies in vitro

Introduction. The demand for honeysuckle berries and planting material is growing. Clonal micropropagation is the most effective method for industrial plantations. The research objective was to study the effect of cytokinins and auxins on Russian and Canadian honeysuckle microshoots and roots. Study objects and methods. The study featured regenerated honeysuckle (Lonicera edulis Turcz.) of three Russian cultivars (Bakcharsky Velikan, Doch Velikana, Yugana) and two Canadian cultivars (Boreal Beauty, Boreal Beast). The experiment focused on the effect of sterilizing agents and sterilization time on the viability of honeysuckle explants at the stage of culture introduction in vitro. The effect of the growth regulator Cytodef in the QL nutrient medium on organogenesis was studied at the stage of micropropagation proper, the effect of auxin IBA on plant root formation – at the stage of rooting in vitro. Results and discussion. The greatest viability of honeysuckle explants (80–94%) was registered in the samples affected by Lizoformin 3000 (5%) and silver nitrate (0.2%) as sterilizing agents with a sterilization time of 10 min at the stage of in vitro culture introduction. The biggest quantity (8.8 pcs.) and total length (40.1 cm) of microshoots were observed when the content of cytokinin Cytodef in the culture medium QL was 0.3 mg/L at the stage micropropagation proper. The Boreal Beast cultivar had the largest total length of shoots (29.0 cm). The biggest quantity (5.5 pcs.) and total length (30.8 cm) of roots resulted from 0.5 mg/L of auxin IBA at the stage of rooting in vitro. Coconut substrate produced the highest survival rate (92–99%) at the stage of adaptation to non-sterile conditions in vivo, with the greatest number of leaves (8.1–10.2 pcs.) observed in Canadian cultivars. Conclusion. Cytodef and IBA proved to be effective growth-regulating substances for microplants of Russian and Canadian honeysuckle cultivars in vitro, which makes them promising for berry plantations.

Preferences Single-Peaked on a Tree: Multiwinner Elections and Structural Results

A preference profile is single-peaked on a tree if the candidate set can be equipped with a tree structure so that the preferences of each voter are decreasing from their top candidate along all paths in the tree. This notion was introduced by Demange (1982), and subsequently Trick (1989b) described an efficient algorithm for deciding if a given profile is single-peaked on a tree. We study the complexity of multiwinner elections under several variants of the Chamberlin–Courant rule for preferences single-peaked on trees. We show that in this setting the egalitarian version of this rule admits a polynomial-time winner determination algorithm. For the utilitarian version, we prove that winner determination remains NP-hard for the Borda scoring function; indeed, this hardness results extends to a large family of scoring functions. However, a winning committee can be found in polynomial time if either the number of leaves or the number of internal vertices of the underlying tree is bounded by a constant. To benefit from these positive results, we need a procedure that can determine whether a given profile is single-peaked on a tree that has additional desirable properties (such as, e.g., a small number of leaves). To address this challenge, we develop a structural approach that enables us to compactly represent all trees with respect to which a given profile is single-peaked. We show how to use this representation to efficiently find the best tree for a given profile for use with our winner determination algorithms: Given a profile, we can efficiently find a tree with the minimum number of leaves, or a tree with the minimum number of internal vertices among trees on which the profile is single-peaked. We then explore the power and limitations of this framework: we develop polynomial-time algorithms to find trees with the smallest maximum degree, diameter, or pathwidth, but show that it is NP-hard to check whether a given profile is single-peaked on a tree that is isomorphic to a given tree, or on a regular tree.

Effect of different date of transplanting for off-season onion production in Central Uttar Pradesh

Off-season onion production of is an important issue to challenge the price fluctuation during different time of year and in different location of the country. The present experiment was conducted at sub-tropical region of central Uttar Pradesh (Lucknow) during kharif, late kharif season of 2018-20 to find out the optimum date of transplanting and choice of suitable cultivar of onion for off-season production. The experiment consisted of eight dates of transplanting (30th August, 10, 20, 30th September, 10, 20, 30th October and 10th November) and two cultivars (Agrifound Dark Red and L-883) which was laid out in factorial randomized block design with three replications. Transplanting on 30th September showed maximum vegetative growth in terms of plant height (66.93 cm), number of leaves per plant (14.99), maxi-mum length of leaf (47.60 cm), neck thickness (23.19 mm) at 120 days after transplanting as well as highest average bulb weight (79.53 g) and bulb yield ( 10.02kg/plot and 382.68 q/ha). Among the two varieties L-883 showed the better performance in respect of growth and yield in off season production. Therefore, it may be concluded that the cultivation of L-883 variety and transplanting on 30th September was found best for off –season production in the sub –tropical agro- climatic region of Center Uttar Pradesh (Lucknow) which may be beneficial for increasing farmers’ income as well as for benefit of costumers keeping the balance between demand and supply.

Combined application of zinc and iron-lysine and its effects on morpho-physiological traits, antioxidant capacity and chromium uptake in rapeseed (Brassica napus L.)

Environmental contamination of chromium (Cr) has gained substantial consideration worldwide because of its high levels in the water and soil. A pot experiment using oil seed crop (rapeseed (Brassica napus L.)) grown under different levels of tannery wastewater (0, 33, 66 and 100%) in the soil using the foliar application of zinc (Zn) and iron (Fe)–lysine (lys) has been conducted. Results revealed that a considerable decline in the plant growth and biomass elevates with the addition of concentrations of tannery wastewater. Maximum decline in plant height, number of leaves, root length, fresh and dry biomass of root and leaves were recorded at the maximum level of tannery wastewater application (100%) compared to the plants grown without the addition of tannery wastewater (0%) in the soil. Similarly, contents of carotenoid and chlorophyll, gas exchange parameters and activities of various antioxidants (superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX)) were also reduced significantly (P < 0.05) with the increasing concentration of tannery wastewater (33, 66 and 100%) in the soil. In addition, a combined application of Zn and Fe-lys reduced the accumulation and uptake of toxic Cr, while boosting the uptake of essential micronutrients such as Zn and Fe in different tissues of the plants. Results concluded that exogenous application of micronutrients chelated with amino acid successfully mitigate Cr stress in B. napus. Under field conditions, supplementation with these micronutrient-chelated amino acids may be an effective method for alleviating metal stress in other essential seed crops.

Evaluation of radish genotypes with special study on sowing geometry at agricultural research institute, Tarnab, Peshawar

The research was carried out on the “Evaluation of Radish genotypes with special study on sowing geometry at Agricultural Research Institute, Tarnab Peshawar”. The experiment was laid out in randomized complete block design having three replications. The experiment comprised with two factors, one was sowing dates(19th Oct., 4th., Nov., and 19th Nov) and the other was different genotypes (Mino, Local Red and Local White). The data were recorded on Days to germination, Germination (%), Days to edible maturity, Number of leaves plant-1, Leaf length plant-1 (cm), Root length plant-1 (cm), Root diameter plant-1 (cm), root fresh weight (g), Plot weight (kg) and yield (t ha-1). Sowing dates significantly affected all yield parameters. Sowing of radish on 19th October has more number of Leaves (17.44 leaves) plant-1, Leaf length plant(22.611 cm), root length plant-1(24.058 cm), root diameter plant-1(3.12 cm) fresh root weight (503.95g), the maximum plot weight (50.90 kg plot-1) and higher yield (62.36t ha-1) was observed whereas the crop sown on 19th November showed the minimum days to germination (8.88 days), germination percentage (96.88%) and minimum days to maturity (53 days). Among genotypes Mino take minimum days to germinate(8.22 days), maximum germination percentage (99.22), minimum days to maturity (52.778), maximum number of leaves (19.44 leaves), leaf length (23.422 cm), greater root length (24.588 cm), maximum root diameter (3.53 cm), higher root fresh weight (536.62g), higher weight per plot (52.22 kg) and maximum yield (63.54t ha-1). The results emphasized that the suitable time of sowing for Mino genotype is 19th October for Peshawar.