Plant Shoot Dry Mass Research Articles

Association Between Fomesafen and Surfactants for the Pre-emergence Control of Euphorbia heterophylla L.

This work was conducted with the objective to determine Euphorbia heterophylla control with fomesafen in association with surfactants applied in pre-emergence, in substrates and soils with different characteristics. Three studies were carried out in pots, conducted in greenhouse, in a completely randomized experimental design. The first two studies consisted of investigating the efficacy of pre-emergence combinations of fomesafen and surfactant in the control of E. heterophylla, applied on different substrates (Study 1) and soils (Study 2) with different textural classes. Study 3 was carried out to evaluate the effect of fomesafen, applied in pre-emergence and in combination with adjuvants with different HLB's (hydrophilic-lipophilic balances). The herbicide efficacy on E. heterophylla and plant shoot dry mass were evaluated. The association of adjuvant to fomesafen, in pre-emergence, reduced plant growth in the different substrates and soils. The fomesafen response was influenced by the addition of surfactants with different HLB's. The increase in organic matter content in substrates or soil was related to the decrease of the effect of the surfactants on the control of E. heterophylla with fomesafen, or the effect was only manifested in higher herbicide dosages. Fomesafen associated with surfactant with HLB of 8.6 provided the highest levels of weed control.

Faba Bean (Vicia faba L.) Nodulating Rhizobia in Panxi, China, Are Diverse at Species, Plant Growth Promoting Ability, and Symbiosis Related Gene Levels.

We isolated 65 rhizobial strains from faba bean (Vicia faba L.) from Panxi, China, studied their plant growth promoting ability with nitrogen free hydroponics, genetic diversity with clustered analysis of combined ARDRA and IGS-RFLP, and phylogeny by sequence analyses of 16S rRNA gene, three housekeeping genes and symbiosis related genes. Eleven strains improved the plant shoot dry mass significantly comparing to that of not inoculated plants. According to the clustered analysis of combined ARDRA and IGS-RFLP the isolates were genetically diverse. Forty-one of 65 isolates represented Rhizobium anhuiense, and the others belonged to R. fabae, Rhizobium vallis, Rhizobium sophorae, Agrobacterium radiobacter, and four species related to Rhizobium and Agrobacterium. The isolates carried four and five genotypes of nifH and nodC, respectively, in six different nifH-nodC combinations. When looking at the species-nifH-nodC combinations it is noteworthy that all but two of the six R. anhuiense isolates were different. Our results suggested that faba bean rhizobia in Panxi are diverse at species, plant growth promoting ability and symbiosis related gene levels.

Effects of TiO2 nanoparticles and water-deficit stress on morpho-physiological characteristics of dragonhead (Dracocephalum moldavica L.) plants

Water-deficit stress is the most important environmental factors limiting plant growth, and production. Nano-titanium dioxide (nano anataseTiO2) can have various profound effects on the crop physiological, biochemical and morphological characteristics. In the present research, the influences of different concentrations ofTiO2 nanoparticles (NPs) (0, 10 and 40 ppm) and water-deficit stress on Dragonhead (Dracocephalum moldavica L.) were investigated in a factorial experiment based on randomized complete block design with three replications. Results showed that under normal irrigation, foliar application of 10 ppm TiO2 NPs increased plant shoot dry mass and essential oils content. Under water-deficit stress condition, plants treated with 10 ppm TiO2 NPs had more proline and much less H2O2 and malondialdehyde content as compared to untreated plants. Therefore, it can be concluded that proper concentration of TiO2 NPs probably can be used as an exogenous stimuli for improvement of shoot growth and essential oil content in plants. Furthermore, water-deficit stress-induced damages such as oxidative stress and membrane damage can be ameliorated by foliar application of TiO2 NPs at appropriate concentrations.

Relative importance of soil physico-chemical characteristics and plant species identity to the determination of soil microbial community structure

The structure of soil microbial communities is affected by biotic and abiotic environmental factors, such as plant community composition and soil chemical characteristics, among others. However, little is known about the relative importance of these factors on soil microbial community structure. The objective of this study was to verify which factor, soil chemical characteristics or plant species identity, is more important to the determination of soil microbial community structure. For this, a factorial experiment with four soil chemical conditions and five plant species were set in a greenhouse. After 80 days of cultivation, the rhizospheric soil microbial community structure was accessed by a multiplex T-RFLP, and the mycorrhizal colonization of roots and plant shoot dry mass were estimated. Plant species showed similar growth responses to different soil chemical conditions, but exhibited different patterns in the control of root mycorrhizal colonization. A principal component analysis (PCA) was performed using the T-RFLP data set and showed that soil chemical condition is the main factor defining the structure of soil microbial community. Archaeal and bacterial communities showed to be more sensitive to changes in the soil chemical environment, suggesting a greater importance of these microbial groups in plant adaptation.

Pathogenicity and potential toxigenicity of seed-borne Fusarium species on soybean and pea.

The effect of 15 Fusarium species on seed germination and early plant development was examined in a laboratory study, together with the potential toxigenicity of selected isolates and the possibility of T-2 toxin production on soybean and pea grain. In germination tests, 33 out of 47 isolates of Fusarium chlamydosporum, F. pseudograminearum, F. sporotrichioides, F. crookwellense, F. verticillioides, F. equiseti, F. semitectum, F. solani, F. poae, F. sambucinum and F. compactum significantly reduced the number of normal soybean seedlings, while only six out of 48 isolates of F. sporotrichioides, F. semitectum and F. chlamydosporum significantly reduced the number of normal pea seedlings. When inoculated on plants grown in Hoagland's media, nearly all Fusarium isolates caused necrosis of soybean and pea root, but neither of them significantly reduced shoot and root dry mass of pea plants, or shoot dry mass of soybean plants. Amplification of tri5 and FUM1 genes, required for trichothecene and fumonisin biosynthesis, was carried out by PCR in 45 Fusarium isolates from soybean and 40 isolates from pea. Positive tri5 PCR reaction was recorded in 19 isolates of F. sporotrichioides, F. crookwellense, F. pseudograminearum, F. poae, F. sambucinum, F. culmorum, F. equiseti and F. chlamydosporum. Positive FUM1 PCR reaction was recorded in 35 out of 38 F. verticillioides and F. proliferatum isolates. The content of T-2 toxin produced by eight F. sporotrichioides isolates inoculated on autoclaved soybean, pea and barley grain ranged from 69.4 to 2595.5 μg/kg. No significant differences were determined between T-2 toxin production on soybean and barley grain, nor on pea and barley grain.

Improving cucumber photosynthetic capacity under NaCl stress by grafting onto two salt-tolerant pumpkin rootstocks

Cucumber plants were either self-grafted or grafted onto two salt-tolerant pumpkin rootstocks Chaojiquanwang (Cucurbita moschata Duch), and Figleaf Gourd (Cucurbita ficifolia Bouche). Plants were grown hydroponically in 0, 30, 60, or 90 mM NaCl for 16 d in greenhouse. Salinity induced a smaller decrease in plant shoot dry mass, leaf area, net photosynthetic rate, and stomatal conductance in the two rootstock-grafted plants compared to the self-grafted plants. In addition, a significant increase in intercellular CO2 concentration, as well as a significant decrease in the initial and total ribulose-1,5-bisphosphate carboxylase/oxygenase activities were observed only in the self-grafted plants under 90 mM NaCl treatment. These results suggest that the use of salt tolerant rootstock can improve cucumber photosynthetic capacity under salt stress through both stomatal and non-stomatal pathways.

Effects of antagonistic fungi, plant growth-promoting rhizobacteria, and arbuscular mycorrhizal fungi alone and in combination on the reproduction of Meloidogyne incognita and growth of tomato

Antagonistic fungi (Aspergillus niger CA and Penicillium chrysogenum CA1), plant growth-promoting rhizobacteria (PGPR) (Burkholderia cepacia 4684 and Bacillus subtilis 7612) and AM fungi (Glomus intraradices KA and Gigaspora margarita AA) were assessed alone and in combination for their effects on the growth of tomato and on the reproduction of Meloidogyne incognita in glasshouse experiments. Application of antagonistic fungus, PGPR, or AM fungus alone or in combination significantly increased the length and shoot dry mass of plants both with and without nematodes. The increase in shoot dry mass caused by Gl. intraradices KA in plants without nematodes was greater than that caused by PGPR or antagonistic fungi. Similarly, the increase in shoot dry mass caused by Bu. cepacia 4684 in plants with nematodes was greater than that caused by P. chrysogenum CA1. Application of Bu. cepacia 4684 caused a 36.1% increase in shoot dry mass of nematode-inoculated plants followed by Ba. subtilis 7612 (32.4%), A. niger CA (31.7%), Gl. intraradices KA (30.9%), Gi. margarita AA (29.9%) and P. chrysogenum CA1 (28.8%). Use of Bu. cepacia 4684 with A. niger CA caused a highest (65.7%) increase in shoot dry mass in nematode-inoculated plants followed by Ba. subtilis 7612 plus A. niger CA (60.9%). Burkholderia cepacia 4684 greatly reduced (39%) galling and nematode multiplication, and the reduction was even greater (73%) when applied with A. niger CA. Antagonistic fungi had no significant effect on root colonization caused by AM fungi. Applying Bu. cepacia 4684 with A. niger CA may be useful in the biocontrol of M. incognita on tomato.

Trade-off between cadmium tolerance and relative growth rate in 10 grass species

Plant species exhibit great differences in heavy metal accumulation and tolerance. In this study we compared interspecific differences in responses to Cadmium (Cd) stress among 10 C 3 grass species by growing hydroponically under the conditions of different Cd treatments (0, 5, 10 and 50 μM). Responses of plant shoot dry mass to Cd treatments (resistance) were separated into avoidance (the response of shoot Cd concentration to Cd treatments) and tolerance (the response of shoot dry mass to shoot Cd concentration). The relative growth rate (RGR) and leaf structural properties of plants were measured under optimum growth condition. There were large differences in resistance, avoidance and tolerance among the species. Avoidance and tolerance were attributed independently to total Cd resistance. Resistance and tolerance were correlated negatively with RGR, leaf water content (LW), specific leaf area (SLA), leaf elongation rate (LER), and leaf length (LL), but the leaf dry matter concentration (LMDC), and nuclear DNA content showed a positive correlation with resistance and tolerance. These results indicate a trade-off between growth rate and tolerance to Cd stress. Species with higher Ca/Mg ratios showed low avoidance ( r = −0.943***), suggesting uptake inhibition by Ca 2+ to develop avoidance against Cd stress.

Comparison of Herbaceous Perennial Plant Growth in Seaweed Compost and Biosolids Compost

Liners of angelonia ‘Pink’ (Angelonia angustifolia Benth.), shooting star (Pseuderanthemum laxiflorum), coreopsis ‘Early Sunrise’ (Coreopsis grandiflorum Hogg ex Sweet.), and scutellaria ‘Purple Fountains’ (Scutellaria costaricana H. Wendl.) were transplanted into containers filled with, by volume, 1) 100% compost; 2) 60% compost, 25% vermiculite, 15% perlite; 3) 30% compost, 30% sphagnum peat, 25% vermiculite, 15% perlite; 4) 0% compost, 60% sphagnum peat, 25% vermiculite, 15% perlite. Two compost products were evaluated: SW, a 1:1 by volume mixture of partially composted seaweed and partially composted yard trimmings and SYT, a 1:1 by weight mixture of biosolids compost and yard trimmings compost. There was no difference in angelonia shoot dry mass among the different percentages of SW compost but angelonia plants grown in 0 and 30% SYT had greater shoot dry mass than plants grown in 60 or 100% SYT. Shoot dry mass of shooting star plants increased as the percentage of SYT compost increased from 0 to 30 % and then decreased while shoot dry mass of plants grown in SW compost decreased as the percentage of compost increased. There was no difference in coreopsis shoot dry mass or scutellaria shoot dry mass between the two compost products and there also was no difference in shoot dry mass among the different percentages of either compost product.

Growth of Impatiens ‘Accent Red’ In Three Compost Products

Growth of Impatiens wallerana Hook. ‘Accent Red’ was evaluated in three composted urban waste materials (composted biosolids and yard trash (SYT): 20 percent biosolids/sewage sludge, 44 percent yard trimmings, and 36 percent mixed paper; composted refuse fuel residues with biosolids and yard trash (RYT): 74 percent refuse-derived fuel residuals, 10 percent biosolids/sewage sludge, and 16 percent yard trimmings; and composted municipal solid waste (MSW): 100 percent municipal solid waste). Treatments consisted of 100 percent composted waste and media in which the composted wastes were combined with control medium components at 60 percent, 30 percent, or 0 percent composted waste, by volume. Shoot dry mass of plants grown in SYT increased as the percentage of SYT in the medium increased, while shoot dry mass of plants grown in MSW linearly decreased from 1.24 g to 0.15 g. There were no significant differences in shoot dry mass of plants grown in different percentages of RYT. Initial medium soluble salt concentrations in MSW media were more than double concentrations measured in SYT and RYT media. Soluble salt concentrations in both the 100 percent and 60 percent MSW media exceeded 1.75 dS.m−1, while the soluble salt concentrations in 100 percent SYT and 100 percent RYT were 0.50 dS.m−1 and 0.61 dS.m−1, respectively. The C:N ratios in 100 percent SYT and RYT were 17 and 15, respectively, while 100 percent MSW had a C:N ratio of 29. The relatively higher level of compost maturity as indicated by lower C:N and soluble salt concentrations contributed to superior growth of impatiens plants in 100 percent SYT and RYT compared to 100 percent MSW.

Auxins Increase Post-transplant Growth of Vinca

Auxins are commonly used to induce root formation during in-vitro culture of higher plants. Because transplanting is often accompanied by root damage and loss of small roots, auxins also could be beneficial in minimizing transplant shock. Vinca (Cataranthus rosea) seeds were germinated in a peat-lite growing mix and transplanted into pots (55 mL) filled with a diatomaceous earth (Isolite) 10 days after planting. Pots were then placed in a tray containing 62.5 mL of auxin solution per pot. Two different auxins [indole-acetic acid (IAA) and naphtylacetic acid (NAA)] were applied at rates ranging from 0.01 to 100 mg/L. Post-transplant growth was slow, possibly because of Fe+2-deficiencies. Both IAA (1–10 mg/L) and NAA (0.01–10 mg/L) significantly increased post-transplant root and shoot growth. As expected, NAA was effective at much lower concentrations than IAA. At 63 days after transplant, shoot dry mass of plants treated with 0.1 mg NAA/L was four times that of control plants, while 10 mg IAA/L increased shoot dry mass three-fold. High rates of both IAA (100 mg/L) and NAA (10–100 mg/L) were less effective. The highest NAA rate (100 mg/L) was phytotoxic, resulting in very poor growth and death of many plants. These results suggest that auxins may be a valuable tool in reducing transplant shock and improving plant establishment.

Compost Usage for Growing Impatiens `Accent Red'

Three compost products [biosolids (SYT), refuse derived fuel residues (RYT), and municipal solid waste (MSW)] were compared to a commercial bedding plant medium of 60% Sphagnum peat: 25% shredded bark: 15% aerolite to support Impatiens wallerana `Accent Red' growth. The treatments consisted of 100% compost as a stand alone medium plus blends in which compost was combined with control medium components at 60% compost or 30% compost. Shoot dry mass of plants grown in 100% SYT and RYT was greater than shoot dry mass of Impatiens plants grown in 100% MSW. Plants grown in SYT showed an increase in shoot dry mass from 1.29 to 1.64 g as the percentage of compost in the mix increased from 0% to 100%, while plants grown in MSW showed a linear decrease in. shoot dry mass from 1.29 to 0.18 g. Shoot dry mass of plants grown in RYT did not differ significantly from 0% to 100% compost in the media.