Rosette Diameter Research Articles

Yellow mealworm frass: A promising organic fertilizer for common sowthistle (Sonchus oleraceus L.) and bristly oxtongue (Helminthotheca echioides (L.) Holub) cultivation

Common sowthistle (Sonchus oleraceus L.) and bristly oxtongue [Helminthotheca echioides (L.) Holub] are winter broad-leaved weeds that have gained interest for cultivation as leafy vegetables. The aim of this study was to examine the effects of frass from the yellow mealworm (Tenebrio molitor L.) on nutrient content in soil, growth parameters, and nutrient content in above-ground plant tissues of common sowthistle and bristly oxtongue. Thus, two pot experiments were carried out with 5 treatments [control, calcium ammonium nitrate (CAN) applied at a dose of 100 kg N ha−1, and insect frass applied at a rate of 3500 kg ha−1 (0.5 % w/w) 7000 kg ha−1 (1 % w/w), and 14,000 kg ha−1 (2 % w/w)]. Our results showed that the lowest values of growth parameters for both plant species were recorded in the control treatment. At the final rosette growth stage [e.g., 152 days after sowing (DAS)], the CAN treatment exhibited the highest values of rosette diameter and above-ground dry weight, followed by the highest rate of insect frass. Similarly, at 152 DAS the SPAD index values in the CAN treatment were 28.4–41.5 % higher compared to the control treatment in both species. Regarding root dry weight, the highest values were found in the CAN and insect frass 2 % treatments. In addition, the application of insect frass significantly enhanced soil fertility, with the highest levels of P and K recorded in the insect frass 2 % treatment. In contrast, the CAN treatment resulted in the highest NO3–N content in the soil (15.83 and 19.26 mg kg−1 in common sowthistle and bristly oxtongue, respectively). Moreover, both P and K content in the above-ground plant tissues had the highest values in the insect frass 2 % treatment, while the content of Mg, Mn, and Cu in plant tissues was not affected by the fertilization sources. Therefore, our findings indicate that insect frass can be an additional option in crop fertilization programs as it can improve both the soil fertility and growth of crops compared to conventional inorganic fertilizer sources. However, the effects of insect frass in mixtures with inorganic fertilizers needs to be taken into consideration in future studies.

An F-box Kelch repeat protein, PmFBK2, from Persicaria minor interacts with GID1b to modulate gibberellin signalling

The F-box protein (FBP) family plays diverse functions in the plant kingdom, with the function of many members still unrevealed. In this study, a specific FBP called PmFBK2, containing Kelch repeats from Persicaria minor, was functionally investigated. Employing the yeast two-hybrid (Y2H) assay, PmFBK2 was found to interact with Skp1-like proteins from P. minor, suggesting its potential to form an E3 ubiquitin ligase, known as the SCF complex. Y2H and co-immunoprecipitation tests revealed that PmFBK2 interacts with full-length PmGID1b. The interaction marks the first documented binding between these two protein types, which have never been reported in other plants before, and they exhibited a negative effect on gibberellin (GA) signal transduction. The overexpression of PmFBK2 in the kmd3 mutant, a homolog from Arabidopsis, demonstrated the ability of PmFBK2 to restore the function of the mutated KMD3 gene. The function restoration was supported by morphophysiological and gene expression analyses, which exhibited patterns similar to the wild type (WT) compared to the kmd3 mutant. Interestingly, the overexpression of PmFBK2 or PmGID1b in Arabidopsis had opposite effects on rosette diameter, seed weight, and plant height. This study provides new insights into the complex GA signalling. It highlights the crucial roles of the interaction between FBP and the GA receptor (GID1b) in regulating GA responses. These findings have implications for developing strategies to enhance plant growth and yield by modulating GA signalling in crops.

Carnitine modulates antioxidative defense in ABI2 mutant under salt stress

Carnitine, a ubiquitous compound in living organisms, fulfills diverse roles in energy metabolism, stress resilience, and detoxification. Its antioxidant and osmolyte traits offer relief to stressed plants. Antagonizing abscisic acid (ABA), carnitine influences ABA-responsive genes. Our study, using Arabidopsis thaliana wild-type Ler. (Landsberg erecta) and ABA-insensitive abi2-1 mutants, explored carnitine’s impact on antioxidative responses and ABI2’s role in salt-induced carnitine metabolism. The application of 5 µM carnitine has alleviated the decrease in RWC, shoot weight, and rosette diameter WT plants caused by 80 mM salt stress for 4 days. Carnitine reduced cell membrane damage and salinity effects, evidenced by decreased lipid peroxidation and H2O2. In contrast, the impaired ABI2 of abi2-1, due to deficient phosphatase activity, further exacerbated the inhibitory effect of carnitine on the enzymes of the ascorbate-glutathione cycle, consequently reducing stress mitigation. While abi2-1 mutants exhibited unchanged superoxide dismutase (SOD) activity, they demonstrated increased catalase and peroxidase activity following carnitine treatment under salt stress compared to WT plants. Conversely, wild-type WT plants treated with carnitine exhibited elevated total glutathione content under salt stress, a response not observed in abi2-1 mutants under carnitine treatment. These results underscore the crucial role of ABI2-dependent ABA signaling in regulating plant carnitine metabolism.

Physiological and growth responses of lettuce plants submitted of 2,4-D simulated drift

Pesticide drift is due to the transport of the active ingredient to areas not targeted by spraying, causing negative effects on the sensitive crops’ development. The aim of this study was to evaluate lettuce response to simulated 2,4-D drift. Experiments were conducted in the greenhouse, in a randomized complete block design with four replications. The treatments consisted of nine different doses of the 2,4-D herbicide, which are: 0; 1.56; 3.125; 6.20; 12.5; 25; 50; 75; and 100% from the recommended dose (670 g a.a. ha-1). The application occurred when the lettuce plants had four to six true leaves. The analyzed variables were visual injury (phytotoxicity), development parameter (phyllochron), growth (rosette diameter and dry mass of the aerial part), and photosynthetic parameters (gas exchange). The lettuce crop showed high sensitivity to the 2,4-D herbicide, with the lowest dose resulting in significant phytotoxic damage to plants, and from 12.5% of the recommended 2,4-D dose, visual injuries were greater than 90%. The plants´ development and growth were negatively affected by the increased drift doses, culminating in enhanced phyllochron and reduction in rosette diameter and dry mass of the aerial part. The gas exchange of the crop was affected from 6.20% of the recommended dose, causing a reduction in the CO2 assimilation rate, stomatal conductance, transpiration rate and rubisco carboxylation efficiency.

Maternal effects and inbreeding depression in post-translocation progeny of Campanula glomerata.

Evaluation of plant translocation success based on fitness-related quantitative traits combined with molecular markers may contribute to a finer assessment of inbreeding, selective and rescue processes, which might have long-term consequences for population dynamics and viability. We investigated fitness traits (seed germination, seedling viability, and juvenile growth and mortality) combined with 15 microsatellite loci of the first post-translocation seed progeny from two translocated populations of Campanula glomerata, an insect-pollinated, self-incompatible perennial herb. We examined whether inbreeding, heterosis through admixture, translocation site and maternal transplant seed source origin and lineage might affect seed quality and juvenile growth in controlled cultivation conditions. Flower production and seed germination of the transplants was higher in one of the two translocation sites, which might be related to differences in soil and vegetation composition and cover. Strong maternal effects related to seed source origin and lineage were found on progeny size, with the largest transplants producing the largest progeny. The differences in rosette diameter were maintained across the whole growth period measured. There was inbreeding depression (rather than heterosis) related to biparental inbreeding at the early progeny growth stage, also expressed through juvenile mortality. Our findings highlight that maternal transplant origin, especially when seed sources consisted of small, fragmented remnants, might have a selective value on fitness in the post-translocation generations. If maternal effects and inbreeding depression persist, they might affect global genetic diversity patterns in the long term. Further admixture in the next generations might buffer maternal and inbreeding effects or lead to outbreeding depression.

Biomedical and agricultural applications of gold nanoparticles (AuNPs): a comprehensive review

Abstract The evolution of engineered nanoparticles (NPs); particularly metallic NPs have played an indispensable role in the development of nanotechnology. Among these NPs, gold nanoparticles (AuNPs) have attracted significant attention and are highly being utilized in several fields due to their exceptional properties. Gold nanoparticles were an emerging subject of intensive research due to their spherical shape, large specific surface area, and quick modification by functional groups. As the demand for AuNPs continuously increases; therefore, there is a pressing need to optimize the scientific approach to fully comprehend and exploit their potential. The effect of AuNPs on plant growth and development can either be beneficial or harmful, depending on the plant species and the concentration of NPs. Moderate concentrations of AuNPs have been found to induce primary and lateral roots, reduce oxidative stress, and elongate rosette diameter, while a higher concentration showed negative effects on plant growth and development. Gold nanoparticles also exhibit potent antibacterial, antiviral, and anticancer properties, making them most beneficial in various sectors, especially in the biomedical field. AuNPs are extensively being utilized across various sectors, but their application in the biomedical field is noteworthy, particularly in bioimaging, biosensing, targeted gene and drug delivery, theranostics, regenerative medicine, and tissue engineering. This review emphasizes the potential applications of AuNPs in diverse sectors including agriculture and biomedical, highlighting their potential impact (positive and negative) on plant growth. Furthermore, the review also aims to signify the mechanism of action of AuNPs and their efficacy against bacteria, viruses, and cancer cells.

Extracellular DNA induces resistance against Frankliniella occidentalis through callose accumulation

AbstractThe plant immune system has evolved to sense and respond to potential threats. When an insect attacks a plant, endogenous molecules called damage-associated molecular patterns (DAMPs) are released into the apoplast, triggering a cascade of intracellular signals. Extracellular DNA (eDNA) is a DAMP signal which activates the plant’s immune responses. However, our understanding of whether the detection of eDNA can lessen the damage caused by herbivores is still restricted. Here, we demonstrate that eDNA treatment in Arabidopsis leaves induced plant resistance against the herbivorous insect Frankliniella occidentalis without compromising the plant’s growth. The number of leaves, rosette diameter, fresh weight, and other growth-related parameters in eDNA-treated plants was comparable to water-treated plants. Besides, eDNA treatment reduced the feeding symptoms of F. occidentalis on Arabidopsis leaves. We further found that enhanced resistance in eDNA-treated plants was accompanied by callose accumulation in the affected area, and using the callose-deficient mutant pmr4-1, we demonstrated the positive role of callose in eDNA-induced resistance (eDNA-IR). Additionally, the induction in the jasmonic acid (JA)-signaling marker genes LOX2 and AOS, and the higher accumulation of Jasmonyl-isoleucine (JA-Ile) and JA revealed the role of jasmonates in eDNA-IR. Finally, we demonstrated that the JA signaling mediates callose deposition in eDNA-treated plants by using the JA response mutant jar1-1. These results advance our knowledge of the ability of eDNA to trigger plant resistance and the underlying mechanisms involved in eDNA-IR.

The Effect of External Treatment of Arabidopsis thaliana with Plant-Derived Stilbene Compounds on Plant Resistance to Abiotic Stresses.

Stilbenes are a group of plant phenolic secondary metabolites, with trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) being recognized as the most prominent and studied member. Stilbenes have a great potential for use in agriculture and medicine, as they have significant activities against plant pathogens and have valuable beneficial effects on human health. In this study, we analyzed the effects of direct application of stilbenes, stilbene precursor, and stilbene-rich extract solutions to the plant foliar surface for increasing the resistance of Arabidopsis thaliana to various abiotic stresses (heat, cold, drought, and soil salinity). Exogenous treatment of A. thaliana with stilbenes (trans-resveratrol, piceid, and spruce bark extract) and phenolic precursor (p-coumaric acid or CA) during germination resulted in considerable growth retardation of A. thaliana plants: a strong delay in the root and stem length of 1-week-old seedlings (in 1.3-4.5 fold) and rosette diameter of 1-month-old plants (in 1.2-1.8 fold), while the 2-month-old treated plants were not significantly different in size from the control. Plant treatments with stilbenes and CA increased the resistance of A. thaliana to heat and, to a lesser extent, to soil salinity (only t-resveratrol and spruce extract) to drought (only CA), while cold resistance was not affected. Plant treatments with stilbenes and CA resulted in a significant increase in plant resistance and survival rates under heat, with plants showing 1.5-2.3 times higher survival rates compared to untreated plants. Thus, exogenous stilbenes and a CA are able to improve plant survival under certain abiotic stresses via specific activation of the genes involved in the biosynthesis of auxins, gibberellins, abscisic acid, and some stress-related genes. The present work provides new insights into the application of stilbenes to improve plant stress tolerance.

Ecophysiological responses of bromelias in the restinga in simulated climate change scenarios.

We investigated the ecophysiological responses of the bromeliads Aechmea nudicaulis and Vriesea procera, seeking to assess their suitability to survive in a climate change scenario (optimistic scenario RCP 2.6 of the IPCC, 2021) in a Restinga environment. To carry out this investigation, we used open-top chambers (OTC). During a period of nine months (June 2022 to February 2023), the bromeliads A. nudicaulis and V. procera were subjected to the following treatments: treatment T: plants transplanted to the environmental conditions of the bare sand of the restinga and subjected to the microclimatic conditions of the OTC's; control C: plants transplanted to the environmental conditions of the bare sand of the restinga. The ecophysiological variables height, rosette diameter, relative water content, specific leaf area and total weight of the plants were evaluated. In addition, dead plants were counted. The OTC's showed an average increase in temperature and VPD (Vapor Pressure Deficit) of 1.6°C and 0.5 Kpa, respectively, and an average reduction in RH (relative humidity) of 5.3%. The results of this study indicated that the increase in local temperature that occurred between the sixth and seventh months evaluated (November and December) created limiting conditions that exceeded the tolerance capacity of the bromeliads studied. Furthermore, the climatic conditions of the OTCs intensified the damage that occurred in the plants, verified here by the reductions in the values ​​of the ecophysiological attributes evaluated in the bromeliads studied. In addition, the high mortality rate (above 50%) reinforces the idea that the climatic conditions of the OTC's induced the bromeliads studied to a senescence process. Therefore, these results are important, as they indicate that even the most optimistic climate change scenario (IPCC 2021 RCP 2.6) can harm the growth and development of these bromeliads, which are essential for the structure and functioning of Restinga communities.

Uticaj kompleksnog đubriva APAVIVA NPK (S) 15:15:15(10) na prinos i biometrijske parametre zelene salate endivije (Cichorium endivia L.)

The effect of the complex fertilizer APAVIVA NPK(S) 15:15:15(10) on the yield and biometric parameters of various varieties of endive lettuce (Cichorium endivia L.) was studied in controlled conditions of a pot experiment. The phytolaboratory maintained optimal temperature, humidity and lighting. UnionPowerStar-40W-T lamps were used in the experiment, diode wavelength: blue (450 nm), red (660 nm). Daylight hours were 15 hours (from 7-00 to 22-00). The application of APAVIVA led to an increase in plant height, leaf rosette diameter, number of leaves and their assimilation surface. The use of mineral fertilizer led to an increase in plant productivity. However, increased mineral nutrition contributed to an accelerated transition to the generative phase of plant development, the formation of flowering shoots and the outflow of nutrients from the leaves to the stem. This had a negative impact on the yield of marketable products - chicory lettuce leaves. The addition of lime material (dolomite flour) together with mineral fertilizer increased plant productivity as well as helped to inhibit the accelerated transition to the generative phase and increase the yield of leaf mass.

Influence of Sowing Time on Plant Growth and Production for some Varieties of Chard, in Western Part of Romania

In Romania, chard is a less cultivated species, being present in some areas of Transylvania, on small areas. This research followed the results regarding chard growth and quantitative and qualitative production, obtained by growing plants in the specific conditions Western Romania. Experiment was bifactorial (5x2 type), with ten experimental variants. Comparative crops were carried out in summer and autumn, respectively, with differences in chard plants development (diameter of leaf rosette, length of leaves and petiole) and in the production achieved by varieties used in this research. For some experimental variants, the yields obtained were over 40 t/ha, being comparable to those obtained and mentioned in literature. Chard leaves content in dry matter as well as vitamin C was also monitored, results being comparable to those obtained in other growing conditions in Europe. Sowing time influenced chard total production, in summer crop being higher compared to autumn one. Also, dry matter and vitamin C content was influenced, crops harvested in autumn registered higher results regarding these traits.

The impact of burial depth on Centaurea diluta emergence and modelling of its growth using a nonlinear regression and artificial neural network.

Centaurea diluta Aiton (North African knapweed) is a major weed concern in Spain as a result of the limited herbicides capable of controlling it, and the limited knowledge of its biology hinders the development of integrated weed management strategies. The current study presents results from two experiments that aimed to: (i) determine the effect of seed burial on seedling emergence; and (ii) model its phenology progression using sigmoidal (SRM) and artificial neural network models (ANN) based on different cohort emergence times. In the first experiment, burial at 2 cm and 5 cm decreased C. diluta emergence by 54% and 90%, respectively, compared to the emergence at 0 cm. In the second experiment, without crop-weed competition conditions, the emergence delay led to reductions in leaf number, rosette diameter, plant height and dry biomass by 63%, 50%, 59% and 93%, respectively. Seed production per plant exceeded 21 469. According to the growth model, leaf number was the most consistent morphological trait and critical for timing weed control actions, so it was used to compare SRMs and ANNs. On average, ANNs increased the precision in 5.72% (± 2.4 leaves) compared to SRMs. This slight performance of ANNs may be valuable for controlling C. diluta because control methods must be applied at the 4-leaf stage to achieve good efficacy. Seed burial at 5 cm depth is an effective method reducing C. diluta emergence. ANNs accurately predicted the leaf number employing environmental variables can help increase the efficiency of C. diluta control actions and reduce the risk of escapes. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ethylene and jasmonate signaling converge on gibberellin catabolism during thigmomorphogenesis in Arabidopsis.

Touch induces marked morphological changes in plants, including reduced rosette diameters and delayed flowering, a process called thigmomorphogenesis. Previous studies have revealed that thigmomorphogenesis in Arabidopsis (Arabidopsis thaliana) results from touch-induced accumulation of jasmonic acid (JA) and GIBBERELLIN 2-OXIDASE7 (GA2ox7) transcripts, which encode a gibberellin (GA) catabolism enzyme, leading to reduced levels of active GAs. However, the mechanisms underlying thigmomorphogenesis remain uncharacterized. Here, we showed that touch induces ethylene (ET) production in Arabidopsis. After touch treatment, ET biosynthesis and signaling mutants exhibited even greater thigmomorphogenic changes and more decreased GA4 contents than did wild-type (WT) plants. Biochemical analysis indicated that the transcription factor ETHYLENE INSENSITIVE3 (EIN3) of the ET pathway binds to the promoter of GA2ox8 (encoding another GA 2-oxidase performing the same GA modification as GA2ox7) and represses GA2ox8 transcription. Moreover, MYC2, the master regulator of JA signaling, directly promoted GA2ox7 expression by binding the G-box motif on GA2ox7 promoter. Further genetic analysis suggested that the ET and JA pathways independently control the expression of GA2ox8 and GA2ox7, respectively. This study reveals that the ET pathway is a novel repressor of touch-induced thigmomorphogenesis and highlights that the ET and JA pathways converge on GA catabolism but play opposite roles to fine-tune GA4 content during thigmomorphogenesis.

Overexpression of chloroplastic Zea mays NADP-malic enzyme (ZmNADP-ME) confers tolerance to salt stress in Arabidopsis thaliana.

The C4 plants photosynthesize better than C3 plants especially in arid environment. As an attempt to genetically convert C3 plant to C4, the cDNA of decarboxylating C4 type NADP-malic enzyme from Zea mays (ZmNADP-ME) that has lower Km for malate and NADP than its C3 isoforms, was overexpressed in Arabidopsis thaliana under the control of 35S promoter. Due to increased activity of NADP-ME in the transgenics the malate decarboxylation increased that resulted in loss of carbon skeletons needed for amino acid and protein synthesis. Consequently, amino acid and protein content of the transgenics declined. Therefore, the Chl content, photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), the quantum yield of photosynthetic CO2 assimilation, rosette diameter, and biomass were lower in the transgenics. However, in salt stress (150mM NaCl), the overexpressers had higher Chl, protein content, Fv/Fm, ETR, and biomass than the vector control. NADPH generated in the transgenics due to increased malate decarboxylation, contributed to augmented synthesis of proline, the osmoprotectant required to alleviate the reactive oxygen species-mediated membrane damage and oxidative stress. Consequently, the glutathione peroxidase activity increased and H2O2 content decreased in the salt-stressed transgenics. The reduced membrane lipid peroxidation and lower malondialdehyde production resulted in better preservation, of thylakoid integrity and membrane architecture in the transgenics under saline environment. Our results clearly demonstrate that overexpression of C4 chloroplastic ZmNADP-ME in the C3 Arabidopsis thaliana, although decrease their photosynthetic efficiency, protects the transgenics from salinity stress.

Oligo-Carrageenan Kappa Increases Expression of Genes Encoding Proteins Involved in Photosynthesis, C, N, and S Assimilation, and Growth in Arabidopsis thaliana.

To analyze the effect of oligo-carrageenan (OC) kappa in the stimulation of growth in Arabidopsis thaliana, plants were sprayed on leaves with an aqueous solution of OC kappa at 1 mg mL-1, 5 times every 2 days and cultivated for 5 or 15 additional days. Plants treated with OC kappa showed an increase in rosette diameter, fresh and dry weight, and primary root length. Plants treated with OC kappa once and cultivated for 0 to 24 h after treatment were subjected to transcriptomic analyses to identify differentially expressed genes, mainly at 12 h after treatment. Transcripts encoding proteins involved in growth and development and photosynthesis were upregulated as well as enzymes involved in primary metabolism. In addition, plants treated with OC kappa once and cultivated for 0 to 96 h showed increased levels of transcripts encoding enzymes involved in C, N, and S assimilation at 6 and 12 h after treatment that remain increased until 96 h. Therefore, OC kappa increased the expression of genes encoding proteins involved in photosynthesis, C, N, and S assimilation, and growth in A. thaliana.

Expression of TaNCL2-A ameliorates cadmium toxicity by increasing calcium and enzymatic antioxidants activities in arabidopsis

Cadmium (Cd) is a heavy metal that occurs naturally in the environment and is toxic to both animals and plants. The impact of Cd toxicity is shown to be reduced by the exogenous application of calcium (Ca) in crop plants. The sodium/calcium exchanger-like (NCL) protein is involved in Ca enrichment in the cytoplasm by transporting it from the vacuole in the exchange of cytosolic sodium (Na). However, it has not been utilized to ameliorate the Cd toxicity, to date. An elevated expression of TaNCL2-A gene in the root and shoot tissues of bread wheat seedlings, and a higher growth rate of recombinant yeast cells, suggested its role in Cd stress response. The TaNCL2-A expressing transgenic Arabidopsis lines exhibited significant Cd tolerance with increased Ca (∼10-fold) accumulation. The proline content and antioxidant enzymes activities were increased while oxidative stress-related molecules such as H2O2 and MDA were reduced in the transgenic lines. In addition, the growth and yield parameters of transgenic lines such as seed germination rate, root length, leaf biomass, leaf area index, rosette diameter, leaf length and width, and silique count, along with various physiological indicators like chlorophyll, carotenoid, and relative water contents were also improved in comparison to the control plants. Further, the transgenic lines exhibited significant salinity and osmotic stress tolerance, as well. Taken together, these results suggested that the TaNCL2-A could mitigate Cd toxicity along with salinity and osmotic stress. This gene may also be utilized for phytoremediation and Cd sequestration in future studies.

The tRNA-degradation pathway impacts the phenotype and metabolome of Arabidopsis thaliana: evidence from atipt2 and atipt9 knockout mutants

Isopentenyltransferases (IPTs), including adenosine phosphate-isopentenyltransferases (ATP/ADP-IPTs and AMP-IPTs) and tRNA‐isopentenyltransferases (tRNA-IPTs), are responsible for a rate-limiting step of cytokinin (CK) biosynthesis. tRNA-IPTs, which account for the synthesis of cis-Zeatin (cZ)-type CKs, are less understood and have often been thought to play a housekeeping role or have low activity during plant growth and development. Even with increasing evidence supporting the tRNA-degradation pathway and the role of cis-CK metabolites to perform important functions, a fulsome examination at the metabolome level where critical biological effects are normally absent of phenotypic expression, remains unpublished. Here, two Arabidopsis tRNA-IPT knockout mutants, atipt2 and atipt9, with independent disturbance of the pathway leading to cisCKs were investigated at the phenotype and metabolite levels at four stages of plant development: first leaf, inflorescence, siliques, and mature seed. Phenotypic deviations were noted in rosette diameter, number of non-rosette leaves, shoot height, flowering time, flower number, carotenoid content, trichome development, and above-ground fresh mass. Hormone profiling by high-performance liquid chromatography-high resolution tandem mass spectrometry (HPLC-HRMS/MS) showed that the atipt2 mutant accumulates lower total cisCKs in the first leaves and in siliques. The atipt9 mutant showed reduced total cisCKs in first leaves, but, during silique development, it had higher levels of cisCKs in than those of the wild type (WT) plants. Additionally, metabolite detection was performed via an untargeted approach using HPLC-HRMS. A total of 33 significant features differing in abundance between ipt mutants and the WT were putatively identified based on database search. Matched metabolites included those that participate in hormone cross-talk, fatty acid synthesis, seed set and germination, and in stress acclimation. Evidence indicates that cisCK production is important for plant growth and development, in ways distinct from CKs produced from de novo pathway.

Uso de paclobutrazol e etileno na produção envasada de abacaxizeiro ornamental

Abstract The expansion of residential areas has increased the demand for exotic and increasingly compact landscape plants. In this context, this work aimed to evaluate the effects of paclobutrazol (PBZ) and the timing of ethylene application on growth reduction and flowering anticipation in ornamental pineapples grown in pots. The randomized block design was used with factorial arrangement (2 x 5) and 4 replications and 4 plants per plot. The primary treatments are the presence and absence of PBZ. The secondary treatments were five times of floral induction with ethylene: 90; 120; 150; 180; 210 days after transplanting (DAT) the seedlings into the pots. It was evaluated the variables: height ratio between the heights of the pot and the plant; rosette diameter; leaves length ‘D’ and flowering index. At 255 DAT, although the plants did not respond to floral induction with ethylene, only those treated with PBZ were more compact and had different characteristics such as smaller size and a ratio below 1/3 of the height of the vase in relation to the plant that to favor its commercialization, in pot.

Targeted expression of bgl23-D, a dominant-negative allele of ATCSLD5, affects cytokinesis of guard mother cells and exine formation of pollen in Arabidopsis thaliana.

Targeted expression of bgl23-D, a dominant-negative allele of ATCSLD5, is a useful genetic approach for functional analysis of ATCSLDs in specific cells and tissues in plants. Stomata are key cellular structures for gas and water exchange in plants and their development is influenced by several genes. We found the A. thaliana bagel23-D (bgl23-D) mutant showing abnormal bagel-shaped single guard cells. The bgl23-D was a novel dominant mutation in the A. thaliana cellulose synthase-like D5 (ATCSLD5) gene that was reported to function in the division of guard mother cells. The dominant character of bgl23-D was used to inhibit ATCSLD5 function in specific cells and tissues. Transgenic A. thaliana expressing bgl23-D cDNA with the promoter of stomata lineage genes, SDD1, MUTE, and FAMA, showed bagel-shaped stomata as observed in the bgl23-D mutant. Especially, the FAMA promoter exhibited a higher frequency of bagel-shaped stomata with severe cytokinesis defects. Expression of bgl23-D cDNA in the tapetum with SP11 promoter or in the anther with ATSP146 promoter induced defects in exine pattern and pollen shape, novel phenotypes that were not shown in the bgl23-D mutant. These results indicated that bgl23-D inhibited unknown ATCSLD(s) that exert the function of exine formation in the tapetum. Furthermore, transgenic A. thaliana expressing bgl23-D cDNA with SDD1, MUTE, and FAMA promoters showed enhanced rosette diameter and increased leaf growth. Taken together, these findings suggest that the bgl23-D mutation could be a helpful genetic tool for functional analysis of ATCSLDs and manipulating plant growth.

Crescimento de bulbos de Agave angustifolia em diferentes substratos, com doses de fertirrigação e inoculação com Azospirillum brasilense

ABSTRACT: There is little information about the production of agave plants in the nursery, so this research assessed the growth in the nursery of Agave angustifolia plants originating from inflorescence bulbils, subjected to different substrates, fertigation doses, and inoculation with Azospirillum brasilense. The bulbils were established for two months in a 50% peat-50% perlite substrate. One hundred and eighty plants were individually transferred to 3.8 dm3 pots for evaluation in an experiment with three factors: 1) type of irrigation: 1.1) water, or 1.2) fertigation with Steiner’s nutrient solution (NS), NS-50%, or 1.3) NS-100%; 2) inoculation with Azospirillum brasilense, 2.1) inoculated plants, 2.2) non-inoculated plants; 3) substrate, mixtures of bovine manure (BM) + sand (S) in different proportions, Mix1: 75% BM + 25% S; Mix2: 25% BM + 75% S; Mix3: 50% BM + 50% S. Morphological characteristics were quantified for one year. The largest plants were those that were in substrates with 50% BM, and were fertirrigated with NS-100% and inoculated with Azospirillum brasiliense. The smallest plants were those established a in a substrate with the lowest manure content, irrigated with only water and without inoculation, which was respectively 71.6 and 54.10 cm high, 21 and 15.6 leaves, 76.6 and 62.2 mm in stem diameter, 84.4 and 59.8 cm in rosette diameter.