Dry Weight Increment Research Articles

Enhanced Nutrition Programs to Rehabilitate Freeze-stressed Citrus Trees in Subtropical Regions

Citrus spp. trees are not fully dormant during the winter months in the northern hemisphere; therefore, they are susceptible to sporadic freeze events of various magnitudes that could decline tree productivity or be lethal. In Feb 2021, winter storm Uri produced freezing air temperatures for nearly 72 hours, which created several degrees of injuries to citrus orchards in southern Texas. Producers in the area implemented combinations of multiple horticultural practices aimed at remediating injuries from the cold spell to stimulate root and tree recovery. However, there is a gap in our understanding of how practices such as compost application (CA) combined with varying rates of nitrogen (N) might facilitate tree recovery. Therefore, we conducted a 2-year field experiment using two CAs as soil amendments in combination with three N rates (112, 168, and 224 kg·ha−1 N) to evaluate fruit yield and internal quality, root growth, and recovery of ‘Rio Red’ grapefruits (Citrus ×paradisi Macf.) and ‘Marrs’ sweet oranges (Citrus sinensis). The yields of both crops exhibited modest improvement with CA in 2022; however, it was nonsignificant. Moreover, CA elicited more beneficial effects than N rates alone when rehabilitating trees and improving fruit internal quality after freezing events. Grapefruit brix was 4% higher in fruits harvested from trees treated with compost, and grapefruit roots exhibited a two-fold dry weight increment with CA. Sweet oranges from trees in the CA treatment had 22% lower acidity compared with that of untreated trees. Overall, our results indicate that citrus producers in southern Texas and other subtropical citrus-producing regions might facilitate the rehabilitation of tree injuries attributed to mild to moderate freeze events with moderate financial gains with the timely application of compost, which enhanced tree fitness and ameliorated fruit productivity declines during subsequent harvests.

Associative Bacteria and Arbuscular Mycorrhizal Fungus Increase Drought Tolerance in Maize (Zea mays L.) through Morphoanatomical, Physiological, and Biochemical Changes.

Water deficiency has been recognized as a major abiotic stress that causes losses in maize crops around the world. The maize crop is very important due to the range of products that are derived from this plant. A potential way to reduce the damages caused by water deficiency in maize crops is through the association with plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF). To define the mechanisms developed by associative PGPB and AMF in maize that are involved in protection against moderate drought (MD), this study evaluated the biometrical, anatomical, biochemical, and physiological parameters of maize grown under MD and inoculated with different PGPB (Azospirillum brasilense strain Ab-V5 and Bacillus sp. strain ZK) and with AMF. The relative water content did not change in the treatments. The association with ZK increased the shoot:total ratio, total dry weight, maximum quantum yield of photosystem II, vascular cylinder thickness, and vascular cylinder area. The Ab-V5 inoculation led to an increment in root dry weight, the area of metaxylem vessel elements, and nitrate reductase activity. The AMF association did not lead to changes in the measured parameters. The results indicate that the association with PGPB is a relevant alternative to contribute to reducing losses in maize crops under drought. However, AMF is not indicated for this crop under drought.

Cobalt oxide nanoparticles: An effective growth promoter of Arabidopsis plants and nano-pesticide against bacterial leaf blight pathogen in rice

Recently, the application of cobalt oxide nanoparticles (Co3O4NPs) has gained popularity owing to its magnetic, catalytic, optical, antimicrobial, and biomedical properties. However, studies on its use as a crop protection agent and its effect on photosynthetic apparatus are yet to be reported. Here, Co3O4NPs were first green synthesized using Hibiscus rosa-sinensis flower extract and were characterized using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), transmission/scanning electron microscopy methods. Formation of the Co3O4NPs was attested based on surface plasmon resonance at 210 nm. XRD assay showed that the samples were crystalline having a mean size of 34.9 nm. The Co3O4NPs at 200 µg/ml inhibited the growth (OD600 = 1.28) and biofilm formation (OD570 = 1.37) of Xanthomonas oryzae pv. oryzae (Xoo) respectively, by 72.87% and 79.65%. Rice plants inoculated with Xoo had disease leaf area percentage (DLA %) of 57.25% which was significantly reduced to 11.09% on infected plants treated with 200 µg/ml Co3O4NPs. Also, plants treated with 200 µg/ml Co3O4NPs only had significant increment in shoot length, root length, fresh weight, and dry weight in comparison to plants treated with double distilled water. The application of 200 µg/ml Co3O4NPs on the Arabidopsis plant significantly increased the photochemical efficacy of PSII (ΦPSII) and photochemical quenching (qP) respectively, by 149.10% and 125.00% compared to the control while the non-photochemical energy dissipation (ΦNPQ) was significantly lowered in comparison to control. In summary, it can be inferred that Co3O4NPs can be a useful agent in the management of bacterial phytopathogen diseases.

Evaluation of inorganic phosphate solubilizing efficiency and multiple plant growth promoting properties of endophytic bacteria isolated from root nodules Erythrina brucei

BackgroundIn soils, phosphorous (P) mostly exists in fixed/insoluble form and unavailable for plants use in soil solution, hence it is in scarcity. P is fixed in the form of aluminium, iron and manganese phosphates in acidic soils and calcium phosphate in alkaline soils. Phosphate solubilizing bacteria, the ecological engineers play a pivotal role in the mobilization of fixed forms of P by using different mechanisms. The objectives of this study were to evaluate inorganic phosphate solubilizing efficiency and other multiple plant growth promoting traits of Erythrina brucei root nodule endophytic bacteria and to investigate effects of the selected endophytic bacteria on the growth of wheat plant under phosphorous deficient sand culture at greenhouse conditions.ResultsAmong a total of 304 passenger endophytic bacteria, 119 (39%) exhibited tricalcium phosphate (TCP) solubilization; however, none of them were formed clear halos on solid medium supplemented with aluminum phosphate (Al-P) or iron phosphate (Fe–P). Among 119 isolates, 40% exhibited IAA production. The selected nine potential isolates also exhibited potentials of IAA, HCN, NH3 and/or hydrolytic enzymes production. All the selected isolates were potential solubilizers of the three inorganic phosphates (Al-P, Fe–P and TCP) included in liquid medium. The highest values of solubilized TCP were recorded by isolates AU4 and RG6 (A. soli), 108.96 mg L−1 and 107.48 mg L−1, respectively at sampling day3 and 120.36 mg L−1 and 112.82 mg L−1, respectively at day 6. The highest values of solubilized Al-P and Fe–P were recorded by isolate RG6, 102.14 mg L−1 and 96.07 mg L−1, respectively at sampling days 3 and 6, respectively. The highest IAA, 313.61 µg mL−1 was recorded by isolate DM17 (Bacillus thuringiensis). Inoculation of wheat with AU4, RG6 and RG5 (Acinetobacter soli) increased shoot length by 11, 17.4 and 14.6%, respectively compared to the negative control. Similarly, 76.9, 69.2 and 53.8% increment in shoot dry weight is recorded by inoculation with RG6, AU4 and RG5, respectively. These nine potential endophytic isolates are identified to Gluconobacter cerinus (4), Acinetobacter soli (3), Achromobacter xylosoxidans (1) and Bacillus thuringiensis (1).ConclusionAU4, RG6 and RG5 can be potential bio-inoculants candidates as low cost agricultural inputs in acidic and/or alkaline soils for sustainable crop production.

Response of citrus (Citrus sps.) rootstock hybrids to PEG induced drought under hydroponic system

Present study was carried out at the glasshouse facility of the ICAR-Indian Agricultural Research Institute, New Delhi during 2020–21 using a simple hydroponic platform to assess the polyethylene glycol (PEG) induced drought impact on shoot-root morphology and physio-biochemical traits of 4 newly developed citrus (Citrus sps.) rootstock hybrids. Hybrid CRH 21-13/14 displayed superior shoot morphological performance in drought, articulated in terms of increment in plant height (4.5%), leaf numbers (9.5%), and dry weight of shoot (7.0%) with the lowest leaf wilting index (LWI). A contrasting pattern was noticed in CRH 23-5/15, CRH 23-9/17 akin to sensitive check Jatti khatti. Hybrid CRH 21-13/14 exhibited extensively, ramified and improved root system, and was able to sustain root growth under drought. It also showed an increment in root tips (116.1%) and forks (12.6%) during drought, whereas the rest hybrids along with sensitive check (Jatti khatti) exhibited a declining trend. The strong positive association of most root traits with relative water content (RWC) and membrane stability index (MSI) underscored the contribution of root traits towards drought avoidance by optimizing water resources. Although all tested hybrids declined total chlorophyll, chlorophyll a/b ratio and CSI (chlorophyll stability index) to varying degrees during drought, CRH 21- 13/14 exhibited minimum decline. Study postulate superior drought tolerance of CRH 21-13/14 conferred by the drought avoidance mechanism and moderate performance of CRH 21-14/14 (Pummelo × Troyer) as against CRH 23-5/15 and CRH 23-9/17 (Pummelo × Morton hybrids).

Matter Production Characteristics and Nitrogen Use Efficiency under Different Nitrogen Application Patterns in Chinese Double-Cropping Rice Systems

Panicle-stage nitrogen fertilizer is popular in parts of China due to its higher nitrogen recovery efficiency compared to basal and tiller nitrogen. However, the effect of conversion from basal to panicle-stage nitrogen on matter production, grain yield, and nitrogen use efficiencies (NUE) in Chinese double-cropping rice systems remains largely unknown. Here, we elucidate the effect by using two types of one-time basal nitrogen patterns (A and B), three panicle-N allocation patterns (C, D, and E), and the local conventional patterns (CK). The two-year experiment demonstrates that E (basal/tiller/spikelet-promoting /spikelet-developing nitrogen = 0:4:3:3) produced the greatest annual grain yield, nitrogen agronomic efficiency, and nitrogen partial productivity. The annual dry matter weight and nitrogen increment of panicle, nitrogen transportation of stems contributes the most to annual yield and NUE. Furthermore, the yield increase could be attributed to the higher effective panicles, plant dry matter weight at tillering, and net photosynthesis rate at heading. Moreover, years and varieties affect the yield in different N treatments. The improvement in the net photosynthesis rate at the milk stage also significantly increases nitrogen recovery efficiency. These findings suggest that it is worth paying attention to the rational ratio of tillering to panicle fertilizer without applying a base fertilizer, to synchronously increase the grain yield, NUE in Chinese double-cropping rice systems.

Investigating the Potential of Endophytic Lactic Acid Bacteria Isolated from Papaya Seeds as Plant Growth Promoter and Antifungal Agent

Endophytic lactic acid bacteria (LAB) isolated from papaya seeds, including a consortium of two LAB isolates, Weissella cibaria PPKSD19 and Lactococcus lactis subsp. lactis PPSSD39 could previously inhibit papaya dieback disease causative agent, Erwinia mallotivora BT-MARDI in vitro, indicating their potential as biofertilizer. However, further characterizations on other plant growth-promoting (PGP) properties of the LABs are pre-requisite to use in agricultural settings as bio-inoculum. Hence, this study aimed to evaluate PGP potentials further and in vitro antifungal activity of the LABs against various plant pathogens. The LAB isolates were tested positive in indole-3-acetic acid (IAA), siderophore, and ammonia production and could solubilize phosphate. Weissella cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 exhibited the strongest in vitro antifungal activity against Fusarium oxysporum TKA and Curvularia lunata. Inoculum concentration of 1×108 cfu/ml of W. cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 mixture showed the highest increment in shoot and root dry weight. In conclusion, W. cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 consortium displayed promising plant probiotic potential. These results highlighted the possibility of the bacterial consortium to be exploited as bioinoculant to promote plant growth and inhibit phytopathogens causing plant diseases.

Effect of acid modified tea-waste biochar on crop productivity of red onion (Allium cepa L.)

Biochar has widely been utilized as an agricultural soil amendment owing to its enhanced surface properties and cost-effectiveness. In the present work, the influence of tea waste biochar (TWBC) upon acid modification on Allium cepa L. (red onion) growth has been studied. Its effect as a soil amendment has also been studied by assessing the nutrient retention, microbial population growth and immobilization of potentially toxic metal ions. A greenhouse experiment was carried out by applying different biochar (BC) ratios (2% and 5% w/w) to soil as the growth media for onion plants. A 2.4 times (2.4 × ) reduction of phosphate from leaching was observed upon BC application at a ratio of 2% than that of 5%. Moreover, red onion plants that grew in the BC-fertilizer amended soil at a 2% ratio showed higher growth compared to that of 5%. A ∼1.3 × and ∼1.2 × increment of total dry weight was observed upon amendment of soil fertilizer system with nitric and sulfuric acid-modified TWBC, respectively. An analysis of the potentially toxic metal ion uptake by the respective plant parts showed that lead uptake by the roots of red onion was ∼8.3 × less in BC amended soil compared to that in contaminated soil. Thus, acid-modified TWBC can be considered a potential soil amendment for an enhanced red onion growth. Employing TWBC as a soil amendment in tropical countries, where tea-waste is in abundance, will boost sustainable agriculture.

Characterization and nodulation capacity of native bacteria isolated from mung bean nodules used as a trap plant in Brazilian tropical soils

Mung bean [Vigna radiata (L.) Wilczek] is a legume of Asian origin with great importance worldwide, particularly in developing countries. It is known for its promiscuous association with soil rhizobia, which provides nitrogen via biological nitrogen fixation (BNF). From the prospective of increasing productivity, efforts are ongoing to identify bacteria that form more efficient symbiotic associations with mung bean. In this regard, we evaluated the nodulation of two mung bean cultivars with native rhizobia from 10 samples of tropical Brazilian soil and performed the isolation of bacterial strains present in the nodules. These isolates were characterized morphologically, and grouped based on sequencing of the 16S rRNA gene. The isolates were also evaluated for nodulation capacity in mung bean and BNF efficiency. We found differences in mung bean plant development depending on the soil for both cultivars. In general, the plants cultivated in soil samples from the Atlantic Forest region showed greater nodulation and shoot dry weight compared to the Brazilian Cerrado (tropical savanna). On the basis of an evaluation of nodulation by native rhizobia, we isolated 101 bacterial strains, which were classified according to 16S rRNA gene into nine genera: Bradyrhizobium (66), Rhizobium (19), Mesorhizobium (4), Ensifer (3), Leifsonia (3), Bacillus (3), Agrobacterium (1), Mycolicibacterium (1), and Kaistia (1). Bradyrhizobium was the most abundant genus, and its isolates formed 12 phylogenetic groups. Inoculation assessments revealed that only Bradyrhizobium isolates induced nodule formation in mung bean, with the BNF efficiency of isolates differing depending on phylogenetic group and soil of origin. Plants inoculated with isolates grouped with Bradyrhizobium yuanmingense B071 were found to show greater increases in shoot dry weight. Considering the soil origin, we observed that plants inoculated with Bradyrhizobium isolated from Mato Grosso state soil samples showed smaller increments in nodulation and shoot dry weight. These results suggest that the Bradyrhizobium is the predominant symbiont in the nodules of mung bean grown in Brazilian tropical soils, and its isolates have the potential for mung bean inoculation, especially when grown in soils that provide low nodulation by native rhizobia.

Foliar Feeding With Micronutrients to Overcome Adverse Salinity Effects on Growth and Nutrients Uptake of Bean (Phaseolus vulgaris)

A POT experiment was carried out at the green house of Fertilization Technology Department to investigate the effect of salinity through irrigation water (0.0 and 4000ppm NaCl) and foliar feeding with chelated 12% Fe, Zn and Mn in the form of EDTA each at rate of 1g /L as individual nutrient in addition, to mixture of them on growth and macro and micronutrients uptake of bean bean (Phaseolus vulgaris). Results revealed that salinity resulted in significant reduction in dry weight. However, foliar feeding showed significant increments in the bean dry weight. Moreover, normal soil condition in combination with foliar feeding with the mixture of micronutrients achieved the highest dry weight increments Results also showed that salinity had significant negative effects on micronutrients uptake, while it had no marked effects on macronutrients uptake except K where salinity markedly reduced its uptake. Foliar feeding with micronutrients treatments either as individual nutrient or mixture of them showed significant increases in macro and micronutrients uptake. Spraying bean plants with the mixture on micronutrients showed the highest marked increments as compared with control (water foliar spray) and the other micronutrient treatments. Moreover, the interaction between salinity and micronutrient treatments on macro and micronutrients uptake was significant, where; most of calculated macro and micronutrients uptake showed the highest values by spraying bean plants with the mixture treatment and under the normal soil condition. The only exception was N uptake which calculated in bean, stem where, the highest value resulted from the spraying plants with Fe in combination with normal soil condition.

Pengaruh Wadah Semai Berbahan Dasar Organik dan Fungi Mikoriza Arbuskula (FMA) Terhadap Pertumbuhan Semai Balsa (Ochroma bicolor Rowlee)

Balsa (Ochroma bicolor Rowlee) are generally sown using a polybag. Polybag made from plastic that is not easily destroyed or degraded so that it can cause problems for the environment. As an alternative, polybag can be replaced by using organic pot. This research aims to analyze the effect of the treatment of raw materials of organic pot and inoculation Arbuscular Mycorrhizal Fungi (AMF) towards growth of balsa (O. bicolor). This study used Completely Randomized Design (CRD) with two factors. The results showed that treatment of organic pot composition and interaction of addition of AMF has significant effect of height of balsa. A single treatment of organic pot composition has significant effect of total dry weight and diameter increment of balsa. A single treatment by adding AMF has significant effectfor increment of diameter, total dry weight, and percentage of mycorrhiza colonizationat the root ofbalsa.
 Keyword: Arbuscular Mycorrhizal Fungi (AMF), Balsa (O. bicolor), organic pot

Isolation and identification of beneficial orchid mycorrhizal fungi in Bletilla striata (Thunb.) Rchb.f.(Orchidaceae)

ABSTRACT Orchid mycorrhizal fungi (OMF) are essential for orchids growth. Bletilla striata (Thunb.) Rchb.f.(Orchidaceae) has high ornamental and medicinal value. Beneficial OMF isolation is crucial to improve the survival rate of B. striata tissue culture and transplanting. In this study, we isolated and identified the beneficial OMF in B. striata from the roots of sterilized wild B. striata seedlings by culturing in four different mediums. The germination states of B. striata seeds inoculated with diverse OMF were classified and calculated. Fresh and dry weight increments of B. striata seedlings inoculated with diverse OMF were recorded after 90 d of culturing on 1/2 MS medium. ITS sequences of beneficial fungi were amplified by PCR and taxonomically identified using BLAST against the GenBank nucleotide database. Ten kinds of OMF strains were isolated from B. striata and named R1 to R10. R6 significantly promoted B. striata seeds germination (p < .01). R3 and R6 significantly promoted both the fresh and dry weight increments of B. striata seedlings (p < .05). The ITS sequence of R6 was most similar to the sequence of Serendipita. R3 was identified as Schizothecium fimbriatum by 100% ITS identity. R6 and R3 were beneficial OMF in B. striata.

GROWTH AND MINRAL STATUS OF COTTON PLANTS AS AFFECTED BY ABSICISIC ACID AND SALT STRESS

Application of antioxidant materials like absicisic acid to alleviate salinity stress and promote cotton growth is high effectiveness target, whereas cotton plant is an attractive industrial crop. Pot experiment was conducted to evaluate the effect of salinity stress and absicisic acid (antioxidant materials to alleviate salinity stress) on cotton growth and macro nutrients status in shoots of cotton plants. Plants subjected to two salinity levels (2500 and 5000 ppm as diluted sea water), and tap water (250ppm) as control, sprayed absicisic acid (ABA) with two concentrations (20 and 40 ppm of ABA) and distilled water as a control. Salinity decreased stem and leaves dry weight compare to the control treatment. The lower concentrations of ABA (20 and 40 ppm as a foliar spray) improve dry weight of stem and leaves. Reversely, leaves/stem ratio decreased with both concentrations of the absicisic acid. The increment in dry weight of leaves and stem or their sum showed its higher values by application 40 ppm from ABA under the 5000 ppm salinity level and also under fresh water treatment but under the 2500 ppm treatment the highest values were by 20 ppm of growth regulator. Nevertheless, L/S ratio decreased by ABA treatment, whereas, the high concentration of ABA (40ppm) was super than lower concentration (20ppm) under both salinity levels. Generally, it can be used diluted seawater in irrigation of cotton plant with spraying abscisic acid to alleviate the harmful effect of salinity.

Utilization of fly ash and lime to stabilize the expansive soil and to sustain pollution free environment – An experimental study

Abstract Expansive soils are problematic due to the performances of their clay constituent usually have the potential to show their undesirable engineering properties such as low bearing capacity, high shrinkage and swell characteristics. The shrink-swell behaviour makes the soil inappropriate for direct engineering application in its natural form and in order to enhance its engineering quality to make them more feasible for usage, stabilization soil can be done physically or chemically. Soil stabilization has been practiced for quite some time by adding mixtures. An experimental investigation was conducted to study the individual and combined effects admixtures viz., lime and fly ash on the geotechnical characteristics of expansive soil. First, expansive soil is mixed with 4% and 8% of lime and next expansive soil is mixed with 10% Fly ash + 4% Lime and 10% Fly ash + 8% Lime. The result shows that addition of expansive soil with lime alone or with lime and fly ash in different percentages, the liquid limit, plastic limit and plasticity Index, optimum moisture content and differential free swell index decreased, whereas maximum dry unit weight and strength of soil admixtures increased. Flocculated structure with voids filled by admixtures resulting in decrement of plasticity characteristics, optimum moisture content and differential free swell index and increment in maximum dry unit weight thereby strength of soil-admixtures compared to soil alone.

Validation of Best Practice for Barley Production on Acid Soils of Central and Western Highland of Ethiopia: Effect of Liming on Ameliorating Soil Acidity and Soil P - Availability

A field experiment was conducted during 2018 cropping season at two locations (Welmera and Jeldu) in the central and western part of Ethiopia to verify the effect of lime in ameliorating soil acidity, P availability and barley productivity. Two barley production practices: 1.5 * EA (t/ha) of lime with 69 kg/ha P 2 O 5 and a farmer’s practice with no lime as a control were tested using a two plot design approach with 9 replication using farmers as replicates. Laboratory soil analytical results of both study areas showed that the soils are strongly acidic in reaction with low P content. Application of lime resulted in significant changes in some chemical properties of the soils in both locations. Soil acidity components such as soil pH, Exchangeable acidity, and Exchangeable Al were improved due to the application of lime and maximum and minimum values of these parameters were recorded. Availability of P, growth parameters, yield and yield components were significantly increased with application of lime at the two locations. Dry biomass weight increment up to 79.4% and grain yield advantage of 40% was recorded due to liming at Rob Gebeya kebele of welmera district. Similarly, 233%, 205% and 17.3% rise was observed in dry biomass, grain yield and 1000 seed weight over the conventional farmer’s practice/control/ respectively at Ento dale and shikute kebele of Jeldu district. According to the result of the current study, application of lime to acid soils led to slightly higher pH, significant decrease in Exchangeable acidity and a marked development in available soil phosphorus level as related to the non amended soil confirming and demonstrating the fact that applying lime in acidic soil maximize the availability of nutrients especially phosphorus in the soil which is very important for better performance of crops. Keywords: Soil acidity, Element toxicity, Nutrient availability, Crop productivity. DOI : 10.7176/JNSR/9-14-01 Publication date :July 31 st 2019

Biometry, shell resistance and attachment of zebra and quagga mussels at the beginning of their co-existence in large European lakes

In invasive dreissenid communities, the zebra mussel usually appears earlier and then is displaced by the quagga mussel. We analysed length-weight allometric relationships, attachment strength (2 days, 1 week and 1 month of exposure), shell crushing resistance and glycogen content across the entire size range of both species in large shallow European lakes where this displacement has recently occurred. In Lake Balaton (Hungary) and Ijsselmeer (The Netherlands), the soft tissue dry weight increment of zebra mussels per unit length decreased after the quagga mussel invasion and became lower than that of quagga mussels. In Lake Markermeer (the Netherlands), having relatively worse environmental conditions, dry weight increment per unit length was always higher in quagga mussels than in zebra mussels, but no negative change in dry weight increment occurred in zebra mussels during the quagga mussel invasion. Small zebra mussels had more resistant shells and stronger attachment than quagga mussels. These differences were reduced (shell hardness) or reversed (long-term attachment) in larger individuals. Zebra mussels had lower glycogen content than quagga mussels across the entire size range. Thus, the quagga mussel advantage over zebra mussel likely consists in the faster dry weight increment per unit length and higher storage product contents of the former, due to its lower investments in attachment strength and shell crushing resistance.

PARTIÇÃO DA MATÉRIA SECA E DE CARBONO EM MUDAS DE &lt;i&gt;Pinus taeda &lt;/i&gt; L. SUBMETIDAS À TIGMOMORFOGÊNESE

O presente trabalho objetivou quantificar os efeitos da tigmomorfogênese induzida por flexões caulinares na fase de rustificação de mudas de Pinus taeda L. sobre a partição da matéria seca e de carbono. Mudas de Pinus taeda com 22 cm de altura, produzidas em tubetes, foram submetidas a cinco intensidades de flexões caulinares (0, 5, 10, 20 e 40 flexões) realizadas diariamente, com o auxílio de um aparato mecânico, por 60 dias. Ao final, quantificou-se a área foliar e os incrementos na altura e no diâmetro do coleto. Posteriormente, determinaram-se os incrementos na massa de matéria seca de raízes e da parte aérea foram subdivididas em cinco componentes: raiz pivotante, raízes laterais, acículas, casca e lenho. Na matéria seca resultante, foi determinado o teor e conteúdo de carbono. O experimento seguiu o delineamento inteiramente ao acaso com quatro repetições. Os resultados foram submetidos à análise de regressão a 5% de probabilidade de erro. A tigmomorfogênese induzida por flexões caulinares resultou na redução do crescimento em altura, área foliar e matéria seca da parte aérea, mas, com até 20 flexões caulinares, promoveu o aumento da taxa de crescimento em diâmetro e matéria seca do sistema radicular. A alteração no crescimento primário e secundário foi resultante da redistribuição de carbono e do conteúdo de matéria seca no caule e no sistema radicular, principalmente em raízes laterais, através de redução de área foliar. Os resultados sugerem que em mudas perturbadas mecanicamenteo aumento em área foliar deixa de ser o dreno preferencial de carbono, predominando o crescimento de caule e sistema radicular.

Experimental Study on Effect of Waste Plastic Bottle Strips in Soil Improvement

With rapid advancements in technology globally, the use of plastics such as polyethylene bags, bottles etc. is also increasing. The disposal of thrown away wastes pose a serious challenge since most of the plastic wastes are non-biodegradable and unfit for incineration as they emit harmful gases. Soil stabilization improves the engineering properties of weak soils by controlled compaction or adding stabilizers like cement, lime etc. but these additives also have become expensive in recent years. This paper presents a detailed study on the behavior and use of waste plastic in soil improvement. Experimental investigation on reinforced plastic soil results showed that, plastic can be used as an effective stabilizer so as to encounter waste disposal problem as well as an economical solution for stabilizing weak soils. Plastic reinforced soil behaves like a fiber reinforced soil. This study involves the investigation of the effect of plastic bottle strips on silty sand for which a series of compaction, direct shear and California bearing ratio (CBR) tests have been performed with varying percentages of plastic strips and also with different aspect ratios in terms of size. The results reflect that there is significant increment in maximum dry unit weight, Shear Strength Parameters and CBR value with plastic reinforcement in soil. The quantum of improvement in the soil properties depends on type of soil, plastic content and size of strip. It is observed from the study that, improvement in engineering properties of silty sand is achieved at 0.4% plastic content with strip size of (15 mm × 15 mm).

A fed-batch strategy to produce high poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) terpolymer yield with enhanced mechanical properties in bioreactor.

This study reports an efficient fed-batch strategy to improve poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)] terpolymer production by Cupriavidus sp. USMAA2-4 with enhanced mechanical properties in bioreactor. The cultivations have been performed by combining oleic acid with γ-butyrolactone at different concentration ratios with 1-pentanol at a fixed concentration. The batch and fed-batch fermentations have resulted in P(3HB-co-3HV-co-4HB) with compositions of 9-35mol% 3HV and 4-24mol% 4HB monomers. The DO-stat fed-batch fermentation strategies have significantly improved the production with a maximum 4.4-fold increment of cell dry weight (CDW). Besides, appropriate feeding of the substrates has resulted inan increment of terpolymer productivity from 0.086-0.347 g/L/h, with a significantly shortened cultivation time. The bacterial growth and terpolymer formation have been found to be affected by the concentration of carbon sources supplied. Characterization of P(3HB-co-3HV-co-4HB) has demonstrated that incorporation of 3HV and 4HB monomer has significantly improved the physical and thermodynamic properties of the polymers, by reducing the polymer's crystallinity. The tensile strength, Young's modulus of the terpolymer has been discovered to increase with the increase of M w. The fed-batch fermentation strategies employed in this study have resulted in terpolymers with a range of flexible materials having improved tensile strength and Young's modulus as compared to the terpolymer produced from batch fermentation. Possession of lower melting temperature indicates an enhanced thermal stability which broadens the polymer processing window.

Improving Growth, Top Root Yield and Betanin Pigment of Table Beet as a Result of Spraying with Magnesium, Copper and Boron under El-Arish Region

Growth of table beet plant cv. Detroit Suprence, yield, betanin content and TSS in root top were studied due to application of Mg (0.75%, 1.5 %), Cu (15, 30 ppm), and B (30, 60 ppm) as foliar spray through two field experiments were carried out during the winter seasons of 2011-2012 and 2012-2013 at The Experimental Farm of Environ. Agric. Sci. Fac., Arish Univ., North Sinai. The results revealed that higher relative increment in leaf area was achieved by application of Mg at 1.5 % as foliar spray which increased by 90.6 % and 73.0 % in the 1st and 2nd seasons, respectively in comparison with control. Total fresh weight of plant was increased with application of B at 60 ppm in both seasons with relative increments of 47.55% and 43.65 % over the control treatment in 1st and 2nd seasons, respectively. Higher total dry weight per plant was recorded with foliar application of B at 30 ppm in the 1st season, Cu at 15 ppm and B at 60 ppm in the 2nd season. The relative increments in dry weight of plant were 43.45 %, 39.95 %, and 39.10 % over the control for spraying with B at 30 ppm in the 1st season, Cu at 15 ppm and B at 60 ppm in the 2nd season, respectively. Spraying with Cu at 15 ppm and Mg at both concentrations (0.75, 1.5%) achieved the highest contents of chl. a, b and chl. a+b compared to the control treatment. The highest relative yield/fed. was recorded with application of B at a concentration of 60 ppm where it was increased by 38.7 and 42.4% , in the 1st and 2nd seasons, respectively over the control. The content of betanin pigment in cortex increased as a result of spraying with Mg (1.5 %), B (30, 6. Ppm) and Cu (15 ppm), while it increased in core zone due to spray with Mg (0.75 %), Cu (15 ppm) and B(60 ppm) particularly in the 2nd season. The concentration of the pigment in the core zone was lower than in the cortex zone.