Increased Shoot Dry Weight Research Articles

Effects of Trichoderma isolates on tomato growth and inducing its tolerance to water-deficit stress

The fungal species belonging to the Trichoderma genus are the most promising microorganisms which improve plant growth by enhancing nutrient uptake and preventing them against environmental biotic and abiotic stresses. This study was aimed to evaluate the effects of three efficient Trichoderma isolates on tomato growth under water-deficit stress. Ten isolates of Trichoderma were in vitro assayed for auxin production, phosphate solubilizing activity and siderophore production traits, and three efficient isolates were selected for pot culture experiment according to the above assessments. Treatments including inoculation with T1 (Trichoderma longibrachiatum KH), T2 (T. longibrachiatum MA), T3 (T. harzianum), NT1 (negative control; without fungi) and NT2 (positive control; without fungi but with chemical fertilizers) at three soil moisture levels of W0 (no water-deficit stress), W1 (medium stress) and W2 (severe stress) were applied to the pots on seedling transplanting. The results revealed that the shoot and root dry matter, root volume, leaf water potential and stomatal conductance decreased as water-deficit stress increased. However, the decrease was significantly lower in fungal treatments than non-inoculated ones. Inoculations with T1, T2 or T3 increased shoot dry weight by 97.2, 17.2 and 18.96% compared to the positive control (NT2) and by 32.81, 19.41 and 20.42% compared to the negative control (NT1), respectively. The highest root volume was recorded in T1 inoculation. This fungus increased root volume by 91.74% and 96.37% compared to the NT1 and NT2 controls, respectively. Moreover, the T1 inoculation enhanced shoot potassium uptake by 37.23 and 34.36% and that of root by 63.25% and 62.02% compared to the NT1 and NT2 controls, respectively.

Phenotypic variation of cassava root traits and their responses to drought.

Premise of the StudyThe key to increased cassava production is balancing the trade‐off between marketable roots and traits that drive nutrient and water uptake. However, only a small number of protocols have been developed for cassava roots. Here, we introduce a set of new variables and methods to phenotype cassava roots and enhance breeding pipelines.MethodsDifferent cassava genotypes were planted in pot and field conditions under well‐watered and drought treatments. We developed cassava shovelomics and used digital imaging of root traits (DIRT) to evaluate geometrical root traits in addition to common traits (e.g., length, number).ResultsCassava shovelomics and DIRT were successfully implemented to extract root phenotypes, and a large phenotypic variation for root traits was observed. Significant correlations were found among root traits measured manually and by DIRT. Drought significantly decreased shoot dry weight, total root number, and root length by 84%, 30%, and 25%, respectively. High adventitious root number was associated with increased shoot dry weight (r = 0.44) under drought.DiscussionOur methods allow for high‐throughput cassava root phenotyping, which makes a breeding program targeting root traits feasible. We suggest that root number is a breeding target for improved cassava production under drought.

Acclimatization of micropropagated seedlings of pineapple cultivars on organic substrates

Fusariosis constitutes an important hindrance to pineapple farming in Brazil. The cultivars resistant to fusariosis, ‘Vitoria’ and ‘Imperial’, from in vitro culture, are an alternative for crop management. This work evaluates the veg­etative performance of pineapple cultivars propagated by tissue culture in response to the use of organic sub­strates, different in nature and proportion. The experimental design was a completely randomized block, arranged in a 3×5 factorial scheme, with three pineapple cultivars (‘Perola’, ‘Vitoria’, and ‘Imperial’) and five substrates [ORG: Organoamazon®, organic compound; SS: Standard Substrate, soil + sand (1:1 v/v); SS + M + C: SS + sheep manure (M) + carbonized rice husk (C) (2:1:1 v/v); SS + M (3:1 v/v); SS + C (3:1 v/v), unfolded in mean contrasts]. The variables analyzed were shoot and root growth and shoot nutrient content. The vegetative perfor­mance of cultivars, considering the increase of shoot dry weight in the most responsive substrate, was: ‘Perola’ > ‘Vitoria’ > ‘Imperial’. Substrate ORG promoted higher increases in shoot dry weight (259%) and root density (116%) compared to the average of the other substrates. The growth promoted by ORG resulted in higher N, P, K, Ca, and Mg content in pineapple plants. Substrates ORG and SS + M + C are recommended for acclimatiza­tion of in vitro propagated pineapple seedlings in the period of ex vitro seedling acclimatization.

The effect of biochars application on reducing the toxic effects of nickel and growth indices of spinach (Spinacia oleracea L.) in a calcareous soil.

Nowadays, production of biochar from agricultural wastes and its use for the amelioration of contaminated soils with heavy metals is increasing to reduce their negative effects on the growth of various plants. A factorial greenhouse experiment as a completely randomized design with three replications was performed to study the effect of different biochars on the spinach growth in a calcareous soil with different levels of nickel (Ni). The first factor consisted of biochars (control (CL), licorice root pulp (LRB), and rice husk (RHB) prepared at two pyrolysis temperatures (350°C and 550°C), each at 2.5% (w/w)), and the second factor included Ni application levels (0 (N0), 150 (N1), and 300 (N2) mgkg-1 soil). Shoot dry weight (15.0%), photosynthetic pigments (chlorophyll a (46.5%), b (39.5%), carotenoids (52.0%)), and micronutrients uptake (iron (51.8%), manganese (66.4%), copper (62.9%), and zinc (47.1%)) were decreased by increasing the Ni levels from N0 to N2. The activity of antioxidant enzymes (catalase (36.3%) and guaiacol peroxidase (29.3%)) and Ni uptake were increased by the Ni application levels. The biochar treatments (RHB350, RHB550, and LRB550) increased shoot dry weight of spinach through the reduction of Ni uptake, activity of antioxidant enzymes and enhancement of the micronutrients absorption. In general, the effect of the biochars produced at 550°C on the reduction of Ni uptake and the increase in plant growth were better than the biochars produced at 350°C. Finally, it could be concluded that the RHB550 is more suitable for reducing the Ni toxicity and improving the growth indices of the spinach.

Investigating the interaction between photosynthetic photon flux density and far-red radiation in petunia seedlings under sole-source lighting

The ratio of red (R; 600 to 700 nm) to far-red (FR; 700 to 800 nm) radiation regulates phytochrome-mediated photomorphogenic responses to promote radiation capture and survival under shade conditions. The photosynthetic photon flux density (PPFD) is also reduced under shade, making it less clear which shade-avoidance responses are mediated by PPFD, R:FR, or their interaction. We grew seedlings of petunia (Petunia × hybrida 'Wave Blue') at 20°C under six sole-source light-emitting diode (LED) treatments with an 18-h photoperiod. All treatments included 32 µmol m(‑2) s(-1) of blue radiation (LED emission peak = 447 nm) and different intensities (subscript in µmol m(-2) s(-1) of radiation from R (peak = 660 nm) and FR (peak = 731 nm) LEDs: R(64), R(64) + FR(32), R(64) + FR(64), R(256), R(256) + FR(128), and R(256) + FR(256). Stem length, individual leaf area, and shoot dry weight linearly decreased as the R:FR [or estimated phytochrome photoequilibria (PPE)] increased under PPFDs of 96 µmol m(-2) s(-1) (PPFD 96) or 288 µmol m(-2) s(-1) (PPFD 288). Independent of PPE, increasing PPFD decreased stem length and individual leaf area, while increasing shoot dry weight. In addition, inclusion of FR during seedling growth promoted flowering at both PPFDs, but to a greater extent under PPFD 96 than PPFD 288. We conclude that most shade-avoidance responses in petunia are mediated by a decrease in R:FR and PPFD individually, without interaction effects. An exception was for flowering, in which the promotive effect of FR was greater under the lower PPFD.

Aerated Irrigation and Pruning Residue Biochar on N2O Emission, Yield and Ion Uptake of Komatsuna

After irrigation in intensive vegetable cultivation, the soil is filled with water leading to reduced oxygen content of the soil air which will affect vegetable growth and soil N2O emission. In this study, the effect of aerated irrigation and residue biochar on soil N2O emission, yield, and ion uptake of komatsuna grown in Andosol was explored. The experiment included four treatments; control (tap water irrigation), aerated water irrigation, pruning residue biochar with tap water irrigation, and a combination of aerated irrigation and biochar. The results showed that aerated irrigation had no effect on plant growth, but it also increased N2O emission by 12.3% for several days after planting. Plant ion uptake was not affected by aerated irrigation. Biochar amendment increased shoot dry weight and significantly reduced soil N2O emission by 27.9% compared with the control. Plant uptake of N and K also increased with biochar. This study showed that pruning residue biochar has the potential to mitigate N2O emission while increasing vegetable growth and plant nutrient uptake. However, the study soil, Andosol, already has high soil porosity with low bulk density. Thus, further injection of air through irrigation showed no effect on plant growth but increased N2O emission, hence soil aeration was not a limiting factor in Andosol.

Alleviation of drought stress in maize (Zea mays) by inoculation with Azotobacter strains isolated from semi-arid regions

A large area of Iran is located in arid and semi-arid regions; as a result, drought stress is a major problem for the growth of plants. Therefore, it is very important in crop productivity to increase plant tolerance to drought stress. Plant growth promoting rhizobacteria such as Azotobacter may enhance plant growth under drought stress conditions by different mechanisms. In this study, a total of 20 Azotobacter strains were isolated and characterized from 77 rhizosphere soil samples collected from semi-arid regions. The strains were screened for the production of siderophore and IAA, solubilization of phosphate and potassium and growth under drought stress in PEG 6000. The strains were identified by 16S rRNA gene sequencing. The efficient strains were tested on the growth of maize (Zea mays) under drought stress by using three levels of irrigation, including 80, 60 and 40 percent of field capacity in greenhouse conditions. The laboratory results revealed that Az63, Az69 and Az70 were the most effective strains in terms of phosphate and potassium solubilisation, siderophore producion and maximum growth in PEG 6000. At 40 percent of field capacity, the inoculation increased shoot dry weight, plant height, chlorophyll content, nitrogen, phosphorous and iron concentration compared to the control. Az63 and Az70 increased shoot dry weight significantly at 60 percent of field capacity.

Phytobioremediation of cadmium-contaminated soil using combination of Ipomoea reptans Poir and Trichoderma sp. and its effect on spinach growth and yield

This research aimed to study the potential role of Ipomoea reptans and Trichoderma sp. on the absorption of cadmium from cadmium-contaminated soil and its effect on and growth rate and yield of spinach. The research was arranged in a completely randomized blok design with two factors. The first factor was the density of Ipomoea reptans consisting of 0, 2, and 4 plants/polybag. The second factor was the dosage of Trichoderma sp. consisting of 0, 50 and 100% dose of Trichoderma sp . Results of the research showed that Ipomoea reptans with 2 plants/polybag effectively reduced Cd to 66.31% and increased the growth of spinach by 20% on plant height, shoot dry weight of spinach by 35%. Application of 100% dose of Trichoderma sp. effectively reduced Cd by 63.81% and increased spinach plant growth by 18% on plant height and increased shoot dry weight of spinach by 23%). There were interactions of phytoremediator of 2 Ipomoea reptans plants/polybag with bioremediator of 50% Trichoderma sp. that effectively reduced Cd to 71.19% and improved 43% of plant height and leaf number, 31% of leaf area, and 63% of shoot dry weight of spinach plant compared with plants without application of Ipomoea reptans and Trichoderma sp.

Arbuscular mycorrhiza enhances nutrient accumulation in wheat exposed to elevated CO2 and soil salinity

AbstractPlant can establish a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi to improve plant growth and resistance to environmental stresses. The aim of this study was to evaluate the effect of AM on nutrient accumulation of wheat (Triticum aestivum L.) plants under combined elevated CO2 and soil salinity. The effects of CO2 elevation (700 ppm) and salt treatments (0, 1, and 2 g NaCl kg−1 dry soil) on the nutrient accumulation of wheat plants inoculated with AM fungus (Rhizophagus irregularis) were investigated. The AM root colonization was decreased by salt treatment and increased by elevated CO2. AM symbiosis significantly increased shoot dry weight and the accumulation of total C, N, K, Ca, Mg, and Na under elevated CO2 and salt stress. Plant dry biomass was positively correlated with total N, K, Ca, and Mg accumulation, whilst it was negatively correlated with Na accumulation. The concentrations of soluble sugar and glucose in shoots and roots of the AM plants were higher than of the non‐AM plants. It is suggested that AM enhances carbohydrate assimilation and nutrient accumulation in wheat exposed to elevated CO2 and soil salinity.

Growth promotion of rapeseed (Brassica napus) associated with the inoculation of phosphate solubilizing bacteria

Inoculation of microorganisms to improve crop yields and minimize the use of chemical fertilizers is a promising sustainable strategy. The objective of this study was to isolate and identify bacteria from the rhizosphere of rapeseed plants able to solubilize phosphate and promote the growth of this crop. We isolated 40 different bacterial morphotypes which were phenotypically and genotypically characterized. Fourteen isolates (37.8%) were able to solubilize phosphate, 9 of them being epiphytic and 5 endophytic. In greenhouse experiments 7 of these isolates increased shoot dry weight, reaching values similar to those of fertilized plants. Additionally, we determined that survival, growth and biofilm formation ability of these bacteria were not affected by rapeseed root exudates. All the phosphate solubilizing strains able to promote plant growth under greenhouse conditions, with the exception of Bacillus sp. LTAD-52, also increase rapeseed yield (from 21 to 44%) in field trials.

Evaluation of Gelatin as a Biostimulant Seed Treatment to Improve Plant Performance.

The effect of gelatin, used as a biostimulant, was investigated on plant growth in greenhouse studies. Biostimulants are materials that stimulate plant growth, and gelatin, an animal protein hydrolysate, is classified as one type of biostimulant. Gelatin has a unique amino acid composition with a high percentage of proline and hydroxyproline. In a series of experiments gelatin capsules (#3 hard gelatin) containing 7.1 mg nitrogen each, were placed adjacent to seeds of different crop species, at sowing time in individual growing containers and several growth parameters were measured. Different types of hydrolyzed collagen, including granulated gelatin, gelatin hydrolysate, and amino acid mixtures simulating the composition of gelatin were compared on cucumber plant growth. In addition, amino acid mixtures without proline, hydroxyproline, or applied in combination were investigated on cucumber growth. All capsule treatments significantly enhanced crop growth compared to the non-treated control. The treatment with two gelatin capsules placed adjacent to each seed increased shoot dry weight of cucumber, pepper, broccoli, tomato, arugula, and field corn, by 138, 244, 50, 45, 41, and 18 percent, respectively. In an experiment with cucumber alone, there was a positive linear relationship between the number of gelatin capsules from 0 to 3 capsules on plant growth and plant nitrogen content. Cucumber growth and plant nitrogen content was greater from the hydrolyzed collagen treatment compared with the low molecular weight gelatin hydrolysate, a mixture of amino acids or urea and all treatments provided an equivalent amount of nitrogen. Proline and/or hydroxyproline were not responsible for the biostimulant effect. In summary, gelatin provided nitrogen that enhanced plant growth. Moreover, gelatin was an effective biostimulant as the plant growth and nitrogen content was greater from two gelatin capsules compared to amino acid mixture of the same proportion and amount as the gelatin.

Characterization of Mesorhizobium strains for salt tolerance and wilt control: Their potential for plant growth promotion of chickpea (Cicer arietinum L.)

Mesorhizobium sp. indirectly promote the growth of plants as a biocontrol agent by inhibiting the growth of pathogens particularly Fusarium wilt of chickpea. Out of 24 Mesorhizobium isolates obtained from chickpea nodules, eight isolates showed antagonistic effect against Fusarium oxysporum. Salinity stress severely affects growth, nodulation and yield of chickpea. Mesorhizobium isolates were tested for their salt tolerance capacity at 1, 2, 4, 6 and 8% NaCl concentrations. Only two Mesorhizobium isolates MCA5 and MCA22 were found salt-tolerant upto 8% of salt concentration. Maximum increase (45.5%) in shoot dry weight was observed by inoculation of isolate MCA20 at 40 days of chickpea growth under chillum jar conditions, whereas isolate MCA23 resulted in 166.2% increase in root dry weight. Likewise, 112.6% increase in shoot dry weight was observed on inoculation of MCA14 isolate at 80th day of observation. Further extensive research is required to understand the mechanism of potential Mesorhizobium isolates of chickpea in controlling Fusarium wilt disease and salt tolerance. Selection of mesorhizobia with twin functional traits (plant growth promoting and biocontrol agent) can be exploited as future biofertilizer in chickpea.

Transcriptional responses of soybean roots to colonization with the root endophytic fungus Piriformospora indica reveals altered phenylpropanoid and secondary metabolism

Piriformospora indica, a root endophytic fungus, has been shown to enhance biomass production and confer tolerance to various abiotic and biotic stresses in many plant hosts. A growth chamber experiment of soybean (Glycine max) colonized by P. indica compared to uninoculated control plants showed that the fungus significantly increased shoot dry weight, nutrient content, and rhizobial biomass. RNA-Seq analyses of root tissue showed upregulation of 61 genes and downregulation of 238 genes in colonized plants. Gene Ontology (GO) enrichment analyses demonstrated that upregulated genes were most significantly enriched in GO categories related to lignin biosynthesis and regulation of iron transport and metabolism but also mapped to categories of nutrient acquisition, hormone signaling, and response to drought stress. Metabolic pathway analysis revealed upregulation of genes within the phenylpropanoid and derivative pathways such as biosynthesis of monolignol subunits, flavonoids and flavonols (luteolin and quercetin), and iron scavenging siderophores. Highly enriched downregulated GO categories included heat shock proteins involved in response to heat, high-light intensity, hydrogen peroxide, and several related to plant defense. Overall, these results suggest that soybean maintains an association with this root endosymbiotic fungus that improves plant growth and nutrient acquisition, modulates abiotic stress, and promotes synergistic interactions with rhizobia.

Management of Meloidogyne javanica in Okra Using Compost of Pequi Fruit Waste

Pequi waste added to soil can lead to promising results in the management of plant nematodes. This study evaluated the effect of organic compost of pequi fruit waste in the control of Meloidogyne javanica in okra plants. The compost was comprised of cattle manure, sugarcane straw, and pequi rind waste in the ratio 1:1:1. Treatments were five doses of organic compost (0, 5, 10, 20, and 30 g dm-3) and two additional controls: manure (20 g dm-3) and mineral fertilizer (100 mg dm-3 of N), arranged in randomized block design with 10 repetitions. Different treatments were incorporated into pots containing 3 dm-3 of sandy soil infested with 5,000 eggs of M. javanica. Seedlings were transplanted five days later, and evaluated after 60 days of transplanting. Organic compost with pequi waste incorporated to soil increased shoot dry weight and root weight, and reduced the number of egg masses, galls and eggs of M. javanica per gram of root, and reproduction factor. Doses of 20 and 30 g dm-3 increased plant development and reduced the reproductivity of M. javanica compared to mineral fertilizer.

Growth, ionic response, and gene expression of shoots and roots of perennial ryegrass under salinity stress

Growth, ionic responses, and expression of candidate genes to salinity stress were examined in two perennial ryegrass accessions differing in salinity tolerance. The salinity tolerant (PI265349) and sensitive accessions (PI231595) were subjected to 75-mM NaCl for 14 days in a growth chamber. Across two accessions, salinity stress increased shoot dry weight and concentrations of malondialdehyde (MDA) and Na+ in the shoots and roots, but decreased shoot Ca2+ and root K+ concentrations. Salinity stress also increased root expressions of SOS1, PIP1, and TIP1. Plant height and chlorophyll content were unaffected by salinity stress in the tolerant accession but significantly decreased in the sensitive accession. Shoot MDA content did not change in the tolerant accession but increased in the sensitive accession. A more dramatic increase in Na+ was found in the roots of the sensitive accession. Relative to the control, salinity stress reduced expression of SOS1, NHX1, PIP1, and TIP1 in the shoots but increased expression of these genes in the roots of the tolerant accession. Expression levels of SOS1 increased in the roots and expression of NHX1 increased in the shoots but decreased in the roots of the sensitive accession under salinity stress. A decline in PIP1 expression in the shoots and dramatic increases in TIP expression in both shoots and roots were found in the sensitive accession under salinity stress. The results suggested maintenance of plant growth and leaf chlorophyll content, lesser Na+ accumulation in the roots, and lower lipid peroxidation in the shoots which could be associated with salinity tolerance. The decreased expressions of SOS1, NHX1, and TIP1 in the shoots, and increased expressions of NHX1 and PIP1 in the roots might also be related to salinity tolerance in perennial ryegrass.

Foliar application of citric and malic acid to stock plants of rose alters the rooting of stem cuttings

BackgroundAs the world’s best-selling cut flower, there is a high demand for propagated rose plants. Auxins are the dominant growth regulator used to improve the rooting of cutting; however, their application remains a labor-intensive process, and on the other hand, side effects like poor shoot growth exist. Organic acid sprays have enhanced many physiological traits of plants which justified surveying their possible effect on the rooting process in the current study.MethodsDifferent concentrations of citric or malic acid were sprayed to stock plants of rose (Rosa x hybrida cv. ‘Sherbet’) prior to taking cuttings. Malic or citric acid (3, 6, or 9 mM) was applied five times on a 14-day interval in a commercial cut flower production greenhouse. Single-node cuttings were prepared and were rooted under mist. Data collected included rooting percentage, root count, root and shoot length and dry weight, and root-to-shoot ratio (R:S).Results and discussionThe rooting percentage was enhanced by all treatments. Citric acid enhanced root number at 6 mM level followed by 3 mM citric acid. Average root length was increased by all treatments except 3 and 6 mM malic acid. All CA treatments increased shoot length, while it remained unaffected by MA treatments. CA at 3 and 6 mM level and 6 mM MA increased shoot dry weight, but only 9 mM CA increased the root dry weight.ConclusionBoth organic acids had positive effects on rooting response of ‘Sherbet’ roses. However, the mechanism of observed responses to organic acids remains to be studied. While they enhance the physiological performance of stock plants, they can also simultaneously both enhance the rooting as well as the shoot growth of the new plantlets.

Characteristics of growth and quality, and factors contributing to high yield in newly developed rice variety ‘Akidawara’

The newly developed rice variety ‘Akidawara’ (AKI) combines the traits of high yield and highly palatability, and its cultivation is expected to spread. We examined characteristics of growth and quality, and factors contributing to high yield in AKI by comparing with ‘Nipponbare’ (NIP). Grain yield for AKI were 703 g m−2 (9% more than NIP) and 781 g m−2 (14% more than NIP) under the standard and heavy fertilizer regimes. It was also suggested that increase in the sink capacity was the key contributors to the high yield in AKI resulting from a conspicuous increase in the number of spikelets, which is likely due to introgression of the high-yielding variety allele. Furthermore, AKI achieved the similar degree of sink filling in spite of its larger sink capacity. In this point, panicle dry weight increase during ripening (ΔP) was significantly higher for AKI than for NIP despite the fact that no differences in shoot dry weight increase were observed between varieties. The greater ΔP in AKI might be derived from its larger sink capacity and the difference between varieties involves the translocation of nonstructural carbohydrate. In the grain quality, the reduction in perfect grain ratio was negligible and regarded as a small trade-off for AKI’s 14% increase in yield, and grain protein content increased to a lesser degree in AKI at the same yield level. These results suggest that over 700 g m−2 high yield can be achieved with relative high grain quality and lower protein content in AKI.

Heterologous Expression of Secreted Bacterial BPP and HAP Phytases in Plants Stimulates Arabidopsis thaliana Growth on Phytate.

Phytases are specialized phosphatases capable of releasing inorganic phosphate from myo-inositol hexakisphosphate (phytate), which is highly abundant in many soils. As inorganic phosphorus reserves decrease over time in many agricultural soils, genetic manipulation of plants to enable secretion of potent phytases into the rhizosphere has been proposed as a promising approach to improve plant phosphorus nutrition. Several families of biotechnologically important phytases have been discovered and characterized, but little data are available on which phytase families can offer the most benefits toward improving plant phosphorus intake. We have developed transgenic Arabidopsis thaliana plants expressing bacterial phytases PaPhyC (HAP family of phytases) and 168phyA (BPP family) under the control of root-specific inducible promoter Pht1;2. The effects of each phytase expression on growth, morphology and inorganic phosphorus accumulation in plants grown on phytate hydroponically or in perlite as the only source of phosphorus were investigated. The most enzymatic activity for both phytases was detected in cell wall-bound fractions of roots, indicating that these enzymes were efficiently secreted. Expression of both bacterial phytases in roots improved plant growth on phytate and resulted in larger rosette leaf area and diameter, higher phosphorus content and increased shoot dry weight, implying that these plants were indeed capable of utilizing phytate as the source of phosphorus for growth and development. When grown on phytate the HAP-type phytase outperformed its BPP-type counterpart for plant biomass production, though this effect was only observed in hydroponic conditions and not in perlite. Furthermore, we found no evidence of adverse side effects of microbial phytase expression in A. thaliana on plant physiology and seed germination. Our data highlight important functional differences between these members of bacterial phytase families and indicate that future crop biotechnologies involving such enzymes will require a very careful evaluation of phytase source and activity. Overall, our data suggest feasibility of using bacterial phytases to improve plant growth in conditions of phosphorus deficiency and demonstrate that inducible expression of recombinant enzymes should be investigated further as a viable approach to plant biotechnology.

Interaction of biological nitrogen fixation with sowing nitrogen fertilization on common bean in the two seasons of cultivation in Brazil

ABSTRACTSowing nitrogen (N) fertilization can limit biological nitrogen fixation (BNF) reducing common bean yield. The aim of this study was to evaluate the effect of sowing N fertilization plus inoculation on the growth and yield of plants in the two seasons of cultivation in Brazil. In the dry season, N fertilization and inoculation promoted a greater shoot dry weight and higher pod number and yield than only inoculated. In contrast, in the rainy season, this treatment promoted no increase in shoot dry weight and yield compared with the inoculated alone. The number of nodules was greater for the inoculated alone treatment, but nodule weight was not affected by N fertilization in either season. Therefore, sowing N fertilization and inoculation can be an agronomic practice to achieve a higher common bean yield in the dry season, while in the rainy season, the inoculation without N fertilization can support a high yield at a lower cost.

Effect of foliar application of chitosan and salicylic acid on the growth of soybean (Glycine max (L.) Merr.) varieties

Elicitors such as chitosan and salicylic acid could be used not only to increase isoflavone concentration of soybean seeds, but also to increase the growth and seed yield. The objective of the present study was to determine the effects of foliar application of elicitor compounds (i.e. chitosan, and salicylic acid)on the growth of two soybean varieties under dry land conditions. Experimental design was a randomized block design with 2 factors and 3 replications. The first factor was soybean varieties (Wilis and Devon). The second factor was foliar application of elicitors consisted of without elicitor; chitosan at V4 (four trifoliate leaves are fully developed); chitosan at R3 (early podding); chitosan at V4 and R3; salicylic acid at V4; salicylic acid at R3 and salicylic acid at V4 and R3. Parameters observed was plant height at 2-7 week after planting (WAP), shoot dry weight and root dry weight. The results suggest that the Wilis variety had higher plant height 7 WAP than Devon. The foliar application of chitosan increased the plant height at 7 WAP, shoot dry weight and root dry weight. The foliar application of chitosan at V4 and R3 on Devon variety increased shoot dry weight.