An integrated method for irrigation scheduling of potted plants

Hourly meteorological and soil water potential data collected during the summer season on a container crop of 2-year-old plants of Hypericum hidcote were used to develop a methodology that integrates climate-based (AET = ETo × K_c) and soil-based methods (soil water potential measurements by tensiometers) for the automatic control of the irrigation of plants growing in pots. Hourly ETo values were calculated by the CIMIS equation, derived from the Penman formula. Tensiometric data, by a soil-specific tensiometric curve, were transformed into pot water weight and used to estimate actual hourly evapotranspiration (AETt).     

Levels of histone modifications in activated primarily cultured rat hepatic stellate cells

AIM: To investigate the changes of histone modifications during the activation of primarily cultured rat hepatic stellate cells (HSCs) and the relationship between histone modification patterns and α-smooth muscle actin (α-SMA) expression, and to explore the roles of histone modifications in the activation of HSCs. METHODS: The rat HSCs were isolated by in situ perfusion of collagenase combined with density gradient centrifugation, cultured in vitro and identified by immunofluorescence staining. The morphological features of the cells were observed under inverted microscope. The changes of desmin and α-SMA during the activation of HSCs were detected by immunofluorescence staining and Western blotting. The levels of histone 3 lysine 4 dimethylation (H3K4me2), histone 3 lysine 9 dimethylation (H3K9me2), histone 3 lysine 9 acetylation (acH3K9) and histone 4 lysine 12 acetylation (acH4K12) in quiescent HSCs and activated HSCs were determined by Western blotting.RESULTS: The morphology of HSCs shifted from a quiescent phenotype to highly activated myofibroblast during the culture. Immunofluorescence staining and Western blotting showed that the expression levels of α-SMA and desmin were increased over time and reached maximum at 15 d. According to the results of cell morphology and immunofluorescence staining, the cells cultured for 24 h and 15 d were quiescent and activated HSCs, respectively. Compared with quiescent HSCs, there were higher H3K4me2 and lower H3K9me2, acH3K9 and acH4K12 modification levels in activated HSCs (P<0.01). CONCLUSION: Histone modifications show anomalous expression during the activation of primarily cultured rat HSCs. Histone modifications may contribute to the transdifferentiation of HSCs and the development of hepatic fibrosis.     

Simple and efficient methods to generate split roots and grafted plants useful for long-distance signaling studies in Medicago truncatula and other small plants

ABSTRACT: BACKGROUND: Long distance signaling is a common phenomenon in animal and plant development. In plants, lateral organs such as nodules and lateral roots are developmentally regulated by root-to-shoot and shoot-to-root long distance signaling. Grafting and split root experiments have been used in the past to study the systemic long distance effect of endogenous and environmental factors, however the potential of these techniques has not been fully realized because data replicates are often limited due to cumbersome and difficult approaches and many plant species with soft tissue are difficult to work with. Hence, developing simple and efficient methods for grafting and split root inoculation in these plants is of great importance. RESULTS: We report a split root inoculation system for the small legume M. truncatula as well as robust and reliable techniques of inverted-Y grafting and reciprocal grafting. Although the split root technique has been historically used for a variety of experimental purposes, we made it simple, efficient and reproducible for M. truncatula. Using our split root experiments, we showed the systemic long distance suppression of nodulation on a second wild type root inoculated after a delay, as well as the lack of this suppression in mutants defective in autoregulation. We demonstrated inverted-Y grafting as a method to generate plants having two different root genotypes. We confirmed that our grafting method does not affect the normal growth and development of the inserted root; the composite plants maintained normal root morphology and anatomy. Shoot-to-root reciprocal grafts were efficiently made with a modification of this technique and, like standard grafts, demonstrate that the regulatory signal defective in rdn1 mutants acts in the root. CONCLUSIONS: Our split root inoculation protocol shows marked improvement over existing methods in the number and quality of the roots produced. The dual functions of the inverted-Y grafting approach are demonstrated: it is a useful system to produce a plant having roots of two different genotypes and is also more efficient than published shoot-to-root reciprocal grafting techniques. Both techniques together allow dissection of long distance plant developmental regulation with very simple, efficient and reproducible approaches.     

An evaluation of pre-emergent herbicides for container-grown ornamental plants

Two applications of 5 herbicides were evaluated during spring and summer for weed control and phytotoxicity on 25 species of trees, shrubs and herbaceous perennials. Weed control was considered to be effective if herbicide-treated pots contained at most 20% of the weeds in untreated pots. Oxyfluorfen applied at 1.25, 2.5 and 5.0 kg ha^?1 provided effective control of grass and broad-leaved weeds for 8 weeks after the first application, and the 2 higher rates effectively controlled all weeds for 12 weeks after the second application. Oxadiazon at 2.0, 4.0 and 8.0 kg ha^?1 effectively controlled all weeds for 8 weeks after the first application, but only the highest rate was effective 12 weeks after the second application. Napropamide at 5.0, 10.0 and 20.0 kg ha^?1 effectively controlled grasses for up to 12 weeks, but only effectively controlled broad-leaved weeds at the 2 higher rates for 8 weeks after the first application and failed to control them after the second application. Alachlor at 4.0, 8.0 and 16.0 kg ha^?1 and oryzalin + trifluralin at 0.5, 1.0 and 2.0 kg ha^?1 provided effective control of grasses for 8 weeks after the first application. These herbicides at the highest rate also controlled broad-leaved weeds for 8 weeks after the first application. However alachlor and oryzalin + trifluralin failed to provide effective control of any weeds after the second application.Competition from weeds reduced the shoot dry weight (SDW) of unweeded control pots by 20% compared with hand-weeded control pots. None of the herbicides produced visible clamage in any plants. The SDW of 8 species treated with some of the herbicides was significantly lower than the corresponding hand-weeded control plants, and for 6 of these species some herbicide treatments were identified as being possibly phytotoxic. Oxyfluorfen appeared to inhibit the growth of Photinia and Coleonema, and alachlor inhibited the growth of Photinia, Eriostemon, Azalea ‘Splendens’, Lavendula and Coleonema. Oryzalin + trifluralin appeared to inhibit the growth of Bauhinia, and napropamide and oxadiazon inhibited the growth of Coleonema.     

An automated system for controlling drought stress and irrigation in potted plants

Efficient, automated irrigation systems, which can irrigate the substrate of potted plants to a desired level and supply those plants with just the amount of water required for normal plant growth are currently not available. These systems, if developed, could reduce wastage of irrigation water due to excess application. This subsequently could reduce leaching and run-off, and aid growers to cope with increasing regulations of water-use by state governments in the US. Here we describe an irrigation controller that irrigates a substrate to a set-point (volumetric water content, θ) and maintains θ close to that set-point for several weeks. The controller uses calibrated, dielectric moisture sensors, interfaced with a datalogger and solenoid valves, to measure the θ of the substrate every 20 min. When the θ of the substrate drops below the set-point, the controller opens a solenoid valve, which results in irrigation. The θ of the substrate is maintained near a constant level as the datalogger is programmed to increase θ by only 2–3% during each irrigation. Using this controller with bedding plants, we were able to maintain four distinct levels of θ for a prolonged period (40 days), regardless of changes in plant size and environmental conditions. The daily average θ maintained was slightly higher (within 2–3% on any particular day) than the set-point. When the θ measured and maintained by the dielectric moisture sensors was tested using measurements with another probe placed in the same container, the θ measured by both probes was found to be similar, indicating that the controller can indeed maintain θ near the target level. This controller may also have applications in stress physiology, since it allows control over the rate at which drought stress is imposed on plants.     

An efficient technique of mango hybridization

The present study, based on a genetic marker, has shown that the percentage fruit-set from crosses in mango can be doubled simply by doing away with the cumbersome process of bagging the panicles again after cross-pollination by hand. This will facilitate the raising of larger hybrid populations for selection in this highly heterozygous perennial fruit.     

Improvement of staining method for observation of mitotic chromosomes in octoploid strawberry plants

An important strategy to conduct intentional breeding of octoploid strawberry plants is to recognize the functions of every chromosome. To do so, a methodology must be developed to distinguish chromosomes one by one. We reported the possibility of distinguishing chromosomes using light microscopy when somatic cells of octoploid strawberry plants were stained using ordinary methods with lacto-propionic orcein (LPO). However, karyotype analysis of octoploid strawberry plants required clearer chromosome images. This study obtained clearer chromosome images of octoploid Fragaria × ananassa and F. chiloensis plants. Three staining methods were examined: 60% acetic acid (AA) alone, 1.5% LPO alone, and two-step treatments with 60% AA and 1.5% LPO. Collected root tips of the plants were placed in 2 mM 8-hydroxyquinoline solution for 1 h and were subsequently stored at 4 °C for 15 h. The samples were then fixed in a 3:1 absolute alcohol: glacial acetic acid solution for 40 min, followed by mixture with 1N HCl solutions at room temperature for 2 h and then at 60 °C for 10 min. For separate staining using 60% AA and 1.5% LPO, the root tip was expelled on the glass slide with a drop of each solution for a few minutes to stain the chromosomes. For the two-step staining method, the samples stained with 60% AA were frozen at −80 °C for at least 5 min. The cover slip was removed using a razor blade. Subsequently, the specimens were air-dried and stained with the 1.5% LPO for 3 min. Digital images of chromosomes were obtained using light microscopy. Samples of the two-step staining method produced the clearest chromosome images in both F. × ananassa and F. chiloensis. Furthermore, the greatest color difference between the chromosomes and the cytoplasm was obtained from images of the two-step staining method among the three staining methods. These results demonstrate that the two-step staining method is useful for chromosome counting and karyotype analysis in strawberry plants.     

A simple and efficient method for isolating small RNAs from different plant species

Background  

Small RNAs emerged over the last decade as key regulators in diverse biological processes in eukaryotic organisms. To identify and study small RNAs, good and efficient protocols are necessary to isolate them, which sometimes may be challenging due to the composition of specific tissues of certain plant species. Here we describe a simple and efficient method to isolate small RNAs from different plant species.     

Induced androgenesis as a biotechnology method for obtaining DH plants in Daucus carota L.

The influence of various factors on the efficiency of obtaining double haploid lines in anther cultures was examined in Daucus carota L. The impact of the genotype, the formation of donor plants and the growth conditions was investigated. The effects of various regeneration media were analysed. Acclimatisation of androgenic plants and their evaluation were also conducted. Androgenesis was induced on B₅ medium containing 2,4-D and NAA at 0.1 g·L^?1. Depending on the genotype, 1.2–305.3 embryos per 100 anthers were obtained. The highest number of embryos (5.5 per 100 anthers) was obtained from donor plants with the first-order shoots containing one umbel. Cultivation of donor plants under controlled conditions improved the number of embryos from 305 in the open field to 1764 in the growth chamber. Regeneration of plants from androgenetic embryos proceeded most effectively on B₅ medium without hormones and amino acids. Regenerated plants adapted in over 60%. Ploidy analysis showed the presence of 92% of plants with a doubled chromosome set and 8% with a tetraploid number of chromosomes. Plants with a doubled chromosome set were 73% homozygous for the glucose phosphate isomerase isoenzyme and 100% homozygous for the aspartate aminotransferase isoenzyme, which confirms their gametic origin.     

An improved protocol for efficient transformation and regeneration of diverse indica rice cultivars

Background

Common bean (Phaseolus vulgaris L.) is a crop of economic and nutritious importance in many parts of the world. The lack of genomic resources have impeded the advancement of common bean genomics and thereby crop improvement. Although concerted efforts from the "Phaseomics" consortium have resulted in the development of several genomic resources, functional studies have continued to lag due to the recalcitrance of this crop for genetic transformation.

Results

Here we describe the use of a bean pod mottle virus (BPMV)-based vector for silencing of endogenous genes in common bean as well as for protein expression. This BPMV-based vector was originally developed for use in soybean. It has been successfully employed for both protein expression and gene silencing in this species. We tested this vector for applications in common bean by targeting common bean genes encoding nodulin 22 and stearoyl-acyl carrier protein desaturase for silencing. Our results indicate that the BPMV vector can indeed be employed for reverse genetics studies of diverse biological processes in common bean. We also used the BPMV-based vector for expressing the green fluorescent protein (GFP) in common bean and demonstrate stable GFP expression in all common bean tissues where BPMV was detected.

Conclusions

The availability of this vector is an important advance for the common bean research community not only because it provides a rapid means for functional studies in common bean, but also because it does so without generating genetically modified plants. Here we describe the detailed methodology and provide essential guidelines for the use of this vector for both gene silencing and protein expression in common bean. The entire VIGS procedure can be completed in 4-5 weeks.     

An in vivo root hair assay for determining rates of apoptotic-like programmed cell death in plants

ABSTRACT: In Arabidopsis thaliana we demonstrate that dying root hairs provide an easy and rapid in vivo model for the morphological identification of apoptotic-like programmed cell death (AL-PCD) in plants. The model described here is transferable between species, can be used to investigate rates of AL-PCD in response to various treatments and to identify modulation of AL-PCD rates in mutant/transgenic plant lines facilitating rapid screening of mutant populations in order to identify genes involved in AL-PCD regulation.     

A simple and efficient method for the long-term preservation of plant cell suspension cultures

Background  

The repeated weekly subculture of plant cell suspension is labour intensive and increases the risk of variation from parental cells lines. Most of the procedures to preserve cultures are based on controlled freezing/thawing and storage in liquid nitrogen. However, cells viability after unfreezing is uncertain. The long-term storage and regeneration of plant cell cultures remains a priority.     

枇杷属植物基因组DNA提取方法的改进及其应用

以枇杷属的普通枇杷和多种野生枇杷的叶片为材料,对枇杷的DNA提取进行了研究。针对枇杷富含多酚类 等次生物质的特点对枇杷DNA的提取步骤进行了改良处理:采用CTAB-蛋白酶K法加重复抽提,去除枇杷材料中 的相关次生物质,获得了高质量的DNA。所提取的DNA完全能满足PCR、RAPD、AFLP等一些分子生物学实验要 求。     

Control of water and nutrients using a porous tube: a method for growing plants in space

A plant nutrient delivery system that uses a microporous, hydrophilic tube was developed with potential application for crop production in the microgravity of space. The tube contains a nutrient solution and delivers it to the roots. Pumps attached to the tubing create a very small suction that holds the solution within the tube. This system was used to grow wheat (Triticum aestivum cv. Yecora Rojo) for 107 days in a controlled environment at suctions of 0.40, 1.48, or 2.58 kPa. The water absorbed through the pores of the tube by baby diaper sections decreased as suction increased. Correspondingly, final plant biomass, seed number, and spikelet number also tended to decrease as suction increased. The reduced yield at higher suction suggests that the plants experienced water stress, although all suctions were below those typical of soils at field capacity.     

一种简便有效的香蕉小分子RNA提取方法

【目的】提供一种简单、经济、高效的香蕉小分子RNA提取方法,以满足RT-PCR、Northern杂交等分子生物学研究的需要。【方法】以巴西蕉(Musa acuminata L.AAA group,‘Brazilian’)的叶片、雄花、果实和根系为材料,利用改良的CTAB法,结合使用PEG8000分级沉淀DNA和大分子RNA,从而获得小分子RNA。【结果】琼脂糖凝胶电泳显示小RNA带型清晰,无DNA和大分子RNA干扰,说明小RNA质量较好。获得的小RNA经紫外光谱分析其A260/A280的比值在1.872~2.020,产量可达35μg·g-1。以提取的各组织小分子RNA为模板,利用茎环RT-PCR方法在香蕉不同组织小RNA中均检测到mi RNA156a,其扩增片断大小约为70 bp,且测序结果与预测的香蕉mi R156a序列一致。【结论】本实验提供了一种简便高效的香蕉小分子RNA提取方法,可满足RT-PCR、Northern blotting及小RNA文库构建等后续分子生物学研究的需要,为研究人员在实际工作中提供了更多的选择。     

RNA methylation modifications in hepatocellular carcinoma

Epigenetics studies how cells affect the genome and produce related phenotypes without involving changes in nuclear DNA sequences. The main manifestation is that different types of genetic material are modified. These dynamic modifications affect gene expression and play an important regulatory role in the development of a variety of disea-ses, particularly tumors. In recent years, epigenetic modification has more and more new insights in the field of hepatocel-lular carcinoma. RNA methylation and DNA methylation are closely related to the pathogenesis of hepatocellular carcinoma and malignant transformation. This review aims to introduce the latest research advances in various RNA methylation modi-fications in the field of hepatocellular carcinoma. The different types of RNA methylation as the main line to introduce their research details in hepatocellular carcinoma provide new insights and ideas for the research and treatment of hepatocellular carcinoma.     

Progress of PML post-translational modifications in tumor cells

The promyelocytic leukemia (PML) protein is an important part of the PML nuclear bodies (PML-NBs) structure.PML protein is crucial for the assembly of PML-NBs and recruits more than 30 different proteins,including DAXX,ATRX,and small ubiquitin-like molecules involving SUMO to the PML-NBs region.Increased evidence has emerged that a number of different proteins is involved in regulating PML activities by post-translational modifications,such as SUMO modification,ubiquitination and phosphorylation.Here,we review recent studies on the combination of PML and different proteins in the process of apoptosis,replicative senescence and DNA damage response.     

Air ion exposure system for plants

A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.