Number Of Axillary Buds Research Articles

Improve Cannabis sativa micropropagation through increasing air change rate in photoautotrophic and traditional tissue culture

Micropropagation is essential for pathogen-free plant materials. However, the conventional in-vitro micropropagation approach poses challenges for optimal growth and development. This study enhances Cannabis sativa micropropagation by implementing a photoautotrophic tissue culture with increased air change rates. This method relies exclusively on photosynthesis for carbohydrate synthesis, eliminating the need for exogenous sugar supplementation. To overcome the limitations of conventional in vitro culture, the photoautotrophic culture requires higher air exchange in the vessel to supply CO2 for photosynthesis. The research evaluates the effects of varying air change rates, comparing conventional tissue culture (TC) with photoautotrophic micropropagation (PAM). Nodal explants, each with 3–4 fully expanded leaves, were transferred to PAM or TC media in Magenta boxes, undergoing four distinct air change rate treatments: 0.5 (control), 4.1, 7.9, and 14.5 air change per hour. Magenta boxes were placed under controlled chamber conditions, including a photosynthetic photon flux density of 100 µmol·m−2·s−1, 18-hour photoperiod, 25 °C temperature, 70 % relative humidity, and CO2 concentration of 553 µmol·mol−1; data were collected after a 28-day period. Increasing the air change rate in TC (from 0.5 to 7.9 h−1) and PAM (from 0.5 to 14.5 h−1) resulted in a significant 25.1 % and 146.6 % increase in shoot dry mass, respectively. The number of axillary buds per plant exhibited a linear increase response to increasing air change rates only under PAM; as well as a significant difference between PAM (11.5) and TC (8.3) under an air change rate of 7.9 h−1. Particularly advantageous for PAM was simultaneous root growth, escalating from 5.2 to 44.3 mg as the air change rate rose from 0.5 to 14.5 h−1. Implementing the photoautotrophic culture practice not only accelerated Cannabis micropropagation but also maintained outcomes comparable to traditional sugar-based tissue culture, contributing to cost-effective cultivation practices in the Cannabis and tissue culture industries.

Effect of axillary bud number on stem cuttings of sweet potato cv. 'Blesbok' productivity using sack gardening technology

Increasing urbanisation and the rise in global food prices, which results in severe hunger and micronutrient deficiencies, necessitates the identification of innovative, but affordable vegetable growing-based strategies, that can increase access to food by utilising the limited space available in rural and urban areas. Therefore, sack gardening technology could be a solution to both the lack of arable land and water scarcity in urban and rural areas. The objective of the study was to determine whether axillary bud number will have an effect on the agronomic parameters of sweet potato cv. 'Blesbok' produced using the sack gardening technology. The number of axillary buds per stem cutting, namely, 1 (control), 2, 3, 4, and 5 buds, were arranged in RCBD, with 10 replicates. The number of axillary buds had significant effects on vine length (VL), fresh shoot mass (FSM), number of shoots (NOS) and dry shoot mass (DSM). However, no significant effects were observed on fresh tuberous root mass (FTRM), chlorophyll content (CC), stem diameter (ST), tuberous root diameter (TRL), tuberous root length (TRL), dry tuberous root mass (DTRM) and number of tuberous roots (NTR). Relative to the control VL, FSM and DRM was reduced by 8-37, 30-55 and 26-55%, in stem cuttings having 2, 3, 4 and 5 buds, respectively, whereas the NS was increased by 8-17%. The quadratic relationship models were explained by 95, 92, 96 and 98% in VL, NOS, FSM and DSM, respectively. In conclusion, stem cuttings containing 1 and 2 axillary buds showed better growth parameters when grown under sack gardening technology.

Transcriptome analysis during axillary bud growth in chrysanthemum (chrysanthemum×morifolium).

The chrysanthemum DgLsL gene, homologous with tomato Ls, is one of the earliest expressed genes controlling axillary meristem initiation. In this study, the wild-type chrysanthemum (CW) and DgLsL-overexpressed line 15 (C15) were used to investigate the regulatory mechanism of axillary bud development in chrysanthemum. Transcriptome sequencing was carried out to detect the differentially expressed genes of the axillary buds 0 h, 24 h and 48 h after decapitation. The phenotypic results showed that the number of axillary buds of C15 was significantly higher than CW. A total of 9,224 DEGs were identified in C15-0 vs. CW-0, 10,622 DEGs in C15-24 vs. CW-24, and 8,929 DEGs in C15-48 vs. CW-48.GO and KEGG pathway enrichment analyses showed that the genes of the flavonoid, phenylpropanoids and plant hormone pathways appeared to be differentially expressed, indicating their important roles in axillary bud germination. DgLsL reduces GA content in axillary buds by promoting GA2ox expression.These results confirmed previous studies on axillary bud germination and growth, and revealed the important roles of genes involved in plant hormone biosynthesis and signal transduction, aiding in the study of the gene patterns involved in axillary bud germination and growth.

Effect of various LED light on the growth and reproductive of in vitro-derived Indonesian chili pepper (Capsicum annum) Kopay and Laris varieties

Red chili (Capsicum annuum), is one of the horticultural commodities that has a high demand. The production, however, is limited because of unsuitable climate and pest attack. Artificial light using LED light in indoor farming is a potential approach to solve the problem and for the production of metabolites for human health. The aim of this research was to evaluate the effect of various LED lights (white, red, blue, UV and combination red+blue) on two Indonesian chili pepper (Capsicum annuum) varieties Kopay and Laris derived from in vitro cultures and grown in the growth chamber and the greenhouse. Parameters observed were leaves number, plant height, number and weight of axillary buds, number of flower and number of young fruits. The results showed that Laris and Kopay under red and blue light significantly different on height character at 66 DAT. In Laris variety, the highest leaves number observed in plants under red light, while the highest young fruit number observed under blue light. Both red and blue lights grew taller than white light. In Kopay variety, combination red+blue light resulted in higher value in plant height, number of flowers has bloomed, number of axillary buds and weight of axillary buds at 37 DAT. The highest young fruit number observed in plants under white light. These results demonstrated that light wavelength through LED light affected plant growth and development. The findings are crucial for determining the best treatment for producing fruits containing health related-metabolites accumulated in chili peppers of each variety.

Strigolactones modulate cotton fiber elongation and secondary cell wall thickening

Cotton is one of the most important economic crops in the world, and it is a major source of fiber in the textile industry. Strigolactones (SLs) are a class of carotenoid-derived plant hormones involved in many processes of plant growth and development, although the functions of SL in fiber development remain largely unknown. Here, we found that the endogenous SLs were significantly higher in fibers at 20 days post-anthesis (DPA). Exogenous SLs significantly increased fiber length and cell wall thickness. Furthermore, we cloned three key SL biosynthetic genes, namely GhD27, GhMAX3, and GhMAX4, which were highly expressed in fibers, and subcellular localization analyses revealed that GhD27, GhMAX3, and GhMAX4 were localized in the chloroplast. The exogenous expression of GhD27, GhMAX3, and GhMAX4 complemented the physiological phenotypes of d27, max3, and max4 mutations in Arabidopsis, respectively. Knockdown of GhD27, GhMAX3, and GhMAX4 in cotton resulted in increased numbers of axillary buds and leaves, reduced fiber length, and significantly reduced fiber thickness. These findings revealed that SLs participate in plant growth, fiber elongation, and secondary cell wall formation in cotton. These results provide new and effective genetic resources for improving cotton fiber yield and plant architecture.

Influence of light-emitting diodes on the efficiency of valuable woody plants micropropagation

The article presents the results of studying the effect of light-emitting diodes (LEDs) on the efficiency of micropropagation of valuable woody plants. Commercial use of micropropagation requires optimization of various parameters, including light quality and lighting regime. Nowadays, LED have become an alternative source of illumination for plant tissue culture, including woody plants. Recently, along with medicinal herbaceous plants, tree crops have also become widely used as a source of various pharmaceuticals. Therefore, it is promising to optimize the technology of micropropagation for the rapid and massive production of valuable woody plants. The current research focused on analysing the effects of different LEDs on Paulownia sp. micropropagation: white (W), red (R), blue (B), mixed red and blue (R:B), and the Fitotron climate chamber. The fluorescent light was used as a control. Micropropagation efficiency was evaluated using the following parameters: height, number of axillary buds, length of internodes, number and length of roots, and photosynthetic pigment content. P. tomentosa produced the greatest number of roots under R LEDs, while hybrid Paulownia Sieb.Zucc. × Elongata - under W and R LEDs. In hybrid Paulownia Sieb.Zucc. × Elongata, the most intense leaf and internode formation was observed under R:B and R LEDs. The content of chlorophyll a and b in P. tomentosa leaves was significantly higher under R LED, while in HP leaves - under B LED. The obtained results are an important contribution to the commercial use of Paulownia and other valuable woody plants for mass production of plant material with biologically active properties.

Phenotypic Plasticity of Cunninghamialanceolata (Lamb.) Hook. Seedlings in Response to Varied Light Quality Treatments

Effects of light quality on phenotypic plasticity in Cunninghamialanceolata (Lamb.) Hook. seedlings during growth and development, and the underlying mechanisms, were investigated. The seedlings showed distinct morphological adjustments when exposed to an equal photosynthetic photon flux density (400 μmol·m−2·s−1) of different light qualities: monochromatic blue (BL), monochromatic red (RL), monochromatic far-red (FrL), mixed RL and FrL at 1:1 (RFr1:1L), mixed RL and FrL at 1:2 (RFr1:2L), and multi-wavelength white (WL, control). Compared with WL, FrL and BL significantly promoted height increment. However, BL was unfavorable for root growth. The seedling biomass was lower and the root-to-shoot ratio was smaller under BL. RL promoted leaf area enlargement, root growth, axillary bud number, and increased the root-to-shoot ratio, but inhibited stem elongation. Low R/Fr ratios or increased FrL proportion increased seedling stem elongation. The seedling growth under RFr1:1L treatment was poorer than that under other treatments; however, the number of axillary buds was the highest. The plasticity of leaf morphology traits was lower in different treatments, and that of axillary bud traits was crucial in the adaptation of C. lanceolata to light quality. Precise management of light quality and wavelength in controlled environments may maximize the economic efficiency of forest production and enhance its quality.

Effects of clipping frequency on tiller development of crested wheatgrass and hybrid bromegrass at vegetative and reproductive stages

Information on the tiller development of hybrid bromegrass (Bromus inermis × Bromus riparius) is limited. The objective of this study was to evaluate the effect of clipping frequency at the vegetative and reproductive stages on the tiller development and concentrations of sugars of c.v ‘AC Knowles’ hybrid bromegrass compared with c.v ‘Kirk’ crested wheatgrass (Agropyron cristatum L.). This experiment was conducted in a greenhouse using the tillers of the vernalized plants dug from the field. The experimental design was a randomized complete block design (RCBD). Grasses were clipped once or four times at either vegetative or reproductive stage. Regardless of the growth stage, four clippings reduced the tiller number of hybrid bromegrass by 25.9% compared with the undefoliated control, while single clipping had no impact. The four clippings had no impact on the tiller number of crested wheatgrass, while single clipping increased its tiller number on average by 50.4% at both growth stages. Crested wheatgrass produced 16.6% more tillers than hybrid bromegrass under the single clipping. The two grass species had a similar number of axillary buds under different clipping treatments. The axillary bud size of crested wheatgrass was larger than hybrid bromegrass. All axillary buds were viable under the two clipping treatments for both grasses. Four clippings significantly decreased the stem base glucose concentration of the two grasses and the root sucrose concentration of crested wheatgrass. Hybrid bromegrass was less tolerant to frequent clippings than crested wheatgrass. Therefore, intensive grazing of hybrid bromegrass pasture may result in a thin stand.

The Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses

This study was carried out to enlighten students about the effects of apical bud pruning on the growth of axillary buds, as well as determine if this learning model can be implemented in the learning process for horticulture courses in IKIP Saraswati. A fully randomised design method was used to evaluate the effect of apical bud pruning on the growth of axillary buds in spinach plants. samples were assigned to the following groups: the first group (J0) served as the control for the experiment while the experimental groups had varying lengths of pruned apical buds (J1- 3cm, J2- 6cm, J3-9cm and J4- 12 cm). Each test was replicated four times to reduce variability in the experimental results. findings of the study showed that the pruning of apical buds led to an increase in the formation of leaves and the growth of axillary buds. Although the numbers of axillary buds in spinach plants from each treatment group were significantly different, the most notable disparity was observed in J1 plants with an average axillary bud growth of 66. use of this experiment-based learning approach enhanced the students’ ability to use their cognitive, social, psychomotor, and problem-solving skills in the acquisition of knowledge, as well as the analysis and interpretation of data. Based on these findings, it can be concluded that the practical experiment on the effect of apical bud pruning on axillary bud growth should be implemented in the learning process for horticulture courses in IKIP Saraswati. Despite the benefits of the experimental based learning approach, there are certain limitations to its successful implementation in the education system. Some of these include the integration of the experimental learning method to the existing curriculum for horticulture courses, the need to develop new assessment methods in order to evaluate the efficacy of this method, and the insufficient support of teachers and administrators at different tiers of government. This paper also provides recommendations on effective ways to address these challenges and maximize the benefits provided by the experimental based learning methods in the education system. How to Cite this Article Pubmed Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. SRP. 2019; 10(1): 247-256. doi:10.5530/srp.2019.1.41 Web Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. http://www.sysrevpharm.org/?mno=302644993 [Access: March 28, 2021]. doi:10.5530/srp.2019.1.41 AMA (American Medical Association) Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. SRP. 2019; 10(1): 247-256. doi:10.5530/srp.2019.1.41 Vancouver/ICMJE Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. SRP. (2019), [cited March 28, 2021]; 10(1): 247-256. doi:10.5530/srp.2019.1.41 Harvard Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana (2019) Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. SRP, 10 (1), 247-256. doi:10.5530/srp.2019.1.41 Turabian Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. 2019. Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Reviews in Pharmacy, 10 (1), 247-256. doi:10.5530/srp.2019.1.41 Chicago Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. The Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. Systematic Reviews in Pharmacy 10 (2019), 247-256. doi:10.5530/srp.2019.1.41 MLA (The Modern Language Association) Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana. The Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Courses. Systematic Reviews in Pharmacy 10.1 (2019), 247-256. Print. doi:10.5530/srp.2019.1.41 APA (American Psychological Association) Style Dewa Nyoman Oka, Herry Maurits Sumampouw, Ida Bagus Putu Arnyana (2019) Implementation of Experiments on the Effect of Apical Bud Pruning on the Growth of the Axillary Buds of Tahun Spinach (Amarantus hybridus L.) in Horticultural Reviews in Pharmacy, 10 (1), 247-256. doi:10.5530/srp.2019.1.41

Targeted Editing of SlMAPK6 Using CRISPR/Cas9 Technology to Promote the Development of Axillary Buds in Tomato Plants

The mitogen-activated protein kinase (MAPK) cascade signaling system has been relatively conserved throughout the evolution of eukaryotes and is involved in the regulation of growth and development and metabolism. In this study, dwarf tomato plants were used as the research material. First, the tissue-specific expression of SlMAPK6 was measured in wild-type plants by quantitative RT-PCR. The results showed that SlMAPK6 was highly expressed in the tissues of the stems, leaves and flowers but was expressed at low levels in the tissues of the roots, sepals and fruits. Second, SlMAPK6-knockout lines CRISPR-3 and CRISPR-7 were obtained by CRISPR-Cas9 technology and Agrobacterium-mediated transformation. Compared with wild-type, the mutant lines CRISPR-3 and CRISPR-7 showed significant phenotypic characteristics, such as increased numbers of axillary buds and true leaves, thickened stems, and longer leaflets. In addition, to explore the molecular mechanism by which MAPK regulates axillary bud growth, we also showed that SlMAPK6 positively regulates the strigolactone synthesis genes SlCCD7 and SlCCD8 and the gibberellin (GA) synthesis genes GA20ox3 and GA3ox1 and negatively regulates the axillary bud development-related genes Ls, BL and BRC1b/TCP8 and the GA synthesis inhibitory gene GAI. Therefore, SlMAPK6 appears to regulate the synthesis of strigolactone and GA to induce the growth and development of tomato axillary buds.

Resprouting strategies of three native shrub Cerrado species from a morphoanatomical and chemical perspective

This study was carried out in a Cerrado (the largest savanna in the Neotropics) area where pine plantations, introduced in the 1970s, were removed by clear cutting of the trees and burning of the remaining material. After the removal and burning, some native shrub species resprouted. Since resprouting is dependent on buds that can be in the belowground bud-bearing (BBB) organs containing reserves, we selected three resprouting Myrtaceae species for analysis of morphology and anatomy of their BBB organs, to determine which compounds could be accumulated and to investigate the bud protection features. Standard histological techniques were used to analyse the BBB organs. The belowground bud bank at a depth of 10 cm was determined. Nonstructural carbohydrates, total phenolics, and flavonoids were quantified on the roots. The large size of BBB organs suggest that these species were present before plantation establishment and survived plantation management treatments. All species produced a large number of axillary buds. All BBB organs exhibited significant lignification and stored starch and phenolic compounds in the parenchyma cells. The protective features and the storage of reserves associated with the bud-bank allowed the survival and subsequent resprouting of these species, contributing to the regeneration of this disturbed area.

Natural Genetic Variation Underlying Tiller Development in Barley (Hordeum vulgare L).

In barley (Hordeum vulgare L.), lateral branches called tillers contribute to grain yield and define shoot architecture, but genetic control of tiller number and developmental rate are not well characterized. The primary objectives of this work were to examine relationships between tiller number and other agronomic and morphological traits and identify natural genetic variation associated with tiller number and rate, and related traits. We grew 768 lines from the USDA National Small Grain Collection in the field and collected data over two years for tiller number and rate, and agronomic and morphological traits. Our results confirmed that spike row-type and days to heading are correlated with tiller number, and as much as 28% of tiller number variance was associated with these traits. In addition, negative correlations between tiller number and leaf width and stem diameter were observed, indicating trade-offs between tiller development and other vegetative growth. Thirty-three quantitative trait loci (QTL) were associated with tiller number or rate. Of these, 40% overlapped QTL associated with days to heading and 22% overlapped QTL associated with spike row-type, further supporting that tiller development is associated with these traits. Some QTL associated with tiller number or rate, including the major QTL on chromosome 3H, were not associated with other traits, suggesting that some QTL may be directly related to rate of tiller development or axillary bud number. These results enhance our knowledge of the genetic control of tiller development in barley, which is important for optimizing tiller number and rate for yield improvement.

Adequate Management of Post-Fire Defoliation Would Not Affect the Metabolic Activity of Axillary Buds in Grasses

Controlled burning is often used to improve plant structure on rangelands adapted to fire. However, possible damage resulting from post-fire grazing to reappearing desirable plant species may be a serious issue hindering usage of this method. Axillary buds are essential for the re-establishment of the photosynthetic leaf area. We studied if post-burn defoliation affects the number of axillary buds and/or their metabolic activity in Poa ligularis, Nassella tenuis (both desirable plant species) and Amelichloa ambigua (undesirable plant species). We found that the treatments limited neither bud production nor their metabolic activity. The greatest number of total and viable buds in the studied plant species was recorded at the vegetative stage. Poa ligularis had the lowest bud number per tiller but the greatest per plant. Our results thus indicate that moderate defoliation after controlled burning does not affect the survival and productivity of the desirable species.

CENTRORADIALIS Interacts with FLOWERING LOCUS T-Like Genes to Control Floret Development and Grain Number.

CENTRORADIALIS (CEN) is a key regulator of flowering time and inflorescence architecture in plants. Natural variation in the barley (Hordeum vulgare) homolog HvCEN is important for agricultural range expansion of barley cultivation, but its effects on shoot and spike architecture and consequently yield have not yet been characterized. Here, we evaluated 23 independent hvcen, also termed mat-c, mutants to determine the pleiotropic effects of HvCEN on developmental timing and shoot and spike morphologies of barley under outdoor and controlled conditions. All hvcen mutants flowered early and showed a reduction in spikelet number per spike, tiller number, and yield in the outdoor experiments. Mutations in hvcen accelerated spikelet initiation and reduced axillary bud number in a photoperiod-independent manner but promoted floret development only under long days (LDs). The analysis of a flowering locus t3 (hvft3) hvcen double mutant showed that HvCEN interacts with HvFT3 to control spikelet initiation. Furthermore, early flowering3 (hvelf3) hvcen double mutants with high HvFT1 expression levels under short days suggested that HvCEN interacts with HvFT1 to repress floral development. Global transcriptome profiling in developing shoot apices and inflorescences of mutant and wild-type plants revealed that HvCEN controlled transcripts involved in chromatin remodeling activities, cytokinin and cell cycle regulation and cellular respiration under LDs and short days, whereas HvCEN affected floral homeotic genes only under LDs. Understanding the stage and organ-specific functions of HvCEN and downstream molecular networks will allow the manipulation of different shoot and spike traits and thereby yield.

Olive floral development in different hedgerow positions and orientations as affected by irradiance

Irradiance received within the olive hedgerow canopy varies with respect to row orientation, spacing and hedge dimensions. These orchard management criteria offer the opportunity for improving productivity based on understanding the responses of yield-determining processes to irradiance. How irradiance influences inflorescence and flower development, the initial steps in fruit formation, are fundamental components of these processes. In this study we evaluated flowering and fruiting parameters in 5 hedgerow positions (defined by hedgerow side and vertical layer above soil) for N–S (North-South) and E–W (East–West) olive hedgerows (cv. Arbequina). The canopy layers and orientations provided a wide gradient of irradiance received and the relationship of estimated mean daily irradiance for annual and for short periods during floral development and initial fruit set was explored. The numbers of inflorescences and fruits per layer increased from the less illuminated base to more illuminated upper canopy layers. Axillary bud number per shoot also increased toward more illuminated positions, while the proportion of floral buds was unresponsive to the irradiance microenvironment at different positions within the hedgerows. Inflorescence length, node and flower number per inflorescence, and perfect flower percentage increased with position illumination. Ovary quality, indicated by ovule differentiation, was consistently high, independent of position, but ovary size showed some slight significant increases with illumination, mainly in the endocarp. Flowers/inflorescence, fruits/fruiting inflorescence and inflorescence and fruit number per position correlated positively and significantly with estimated irradiance similarly for annual and short periods (r range from 0.49 to 0.86). Despite improved flowering parameters with greater irradiance, no consistent differences among positions were found for percentage of inflorescences bearing fruit and fruit number per inflorescence. Instead, our results indicated that different fruit numbers among canopy positions were primarily due to an irradiance effect on vegetative growth, causing more and longer fruiting shoots and therefore more total flowering sites (nodes) per layer, with only a small contribution by inflorescence structure and flower quality.

In vitro multiplication of pear tree cultivar Cascatense

One main obstacle to the development and expansion of pear tree cultivation in Brazil has been the lack of cultivars adapted to the edaphoclimatic conditions of regions with the potential for pear production. Intending to overcome this hindrance, Embrapa Clima Temperado (Embrapa Temperate Climate) developed and released the cultivar Cascatense, with a low cold requirement (~400 h) better suited for Rio Grande do Sul`s and Santa Catarina`s climate. Still, seedlings of high genetic and sanitary quality are necessary for the establishment of a high-yield orchard. Plants with both sanitary quality and uniformity can be obtained through in vitro micropropagation. Thus, the present study aimed to assess the influence of different culture media (MS, MS¾, WPM, QL, and Himédia), concentrations of sucrose (0, 15, 30, 45, and 60 g L-1), and concentrations of benzylaminopurine (BAP) (0, 0.4, 0.8, 1.2, and 1.6 mg L-1) upon the in vitro multiplication of cultivar Cascatense, to establish an efficient protocol to enhance its propagation and reproducibility. The study included three sequential experiments in which the number of shoots per explant, the length of shoots, the number of axillary buds per shoot, fresh mass, and dry mass of shoots were evaluated. Cultivar Cascatense can be best propagated in vitro with the use of Himédia medium, supplemented with 0.8 mg L-1 of BAP and 30 g L-1 of sucrose.

Lateral Cane Lengths Affect Yield Components in ‘Triple Crown’ Blackberry on Rotating Cross-Arm Trellis and Cane Training System

Primocanes of mature ‘Triple Crown’ blackberry plants were trained on the rotating cross-arm (RCA) trellis. By the end of the summer, as many as 30 lateral branch canes with lengths >3.5 m had developed on three primocanes that had been bent at a 0.50-m height and allowed to extend ˜1.5 m in a horizontal orientation. In winter, the lateral branch canes were shortened to a length of 1.5 m or left unpruned. Data on lateral branch cane length, percent bud break, cluster (e.g., inflorescence) numbers, fruit per cluster, fruit weight, and yield were collected in 2012 and 2013. Pruning reduced lateral branch cane length and axillary bud number but yield components (% bud break, numbers of clusters, and development of inflorescences with more flowers) increased.

The barley Uniculme4 gene encodes a BLADE-ON-PETIOLE-like protein that controls tillering and leaf patterning.

Tillers are vegetative branches that develop from axillary buds located in the leaf axils at the base of many grasses. Genetic manipulation of tillering is a major objective in breeding for improved cereal yields and competition with weeds. Despite this, very little is known about the molecular genetic bases of tiller development in important Triticeae crops such as barley (Hordeum vulgare) and wheat (Triticum aestivum). Recessive mutations at the barley Uniculme4 (Cul4) locus cause reduced tillering, deregulation of the number of axillary buds in an axil, and alterations in leaf proximal-distal patterning. We isolated the Cul4 gene by positional cloning and showed that it encodes a BROAD-COMPLEX, TRAMTRACK, BRIC-À-BRAC-ankyrin protein closely related to Arabidopsis (Arabidopsis thaliana) BLADE-ON-PETIOLE1 (BOP1) and BOP2. Morphological, histological, and in situ RNA expression analyses indicate that Cul4 acts at axil and leaf boundary regions to control axillary bud differentiation as well as the development of the ligule, which separates the distal blade and proximal sheath of the leaf. As, to our knowledge, the first functionally characterized BOP gene in monocots, Cul4 suggests the partial conservation of BOP gene function between dicots and monocots, while phylogenetic analyses highlight distinct evolutionary patterns in the two lineages.

Fire and Nitrogen Alter Axillary Bud Number and Activity in Purple Threeawn

Belowground accumulation of vegetative buds provides a reservoir of meristems that can be utilized following disturbance. Perennial grass bud banks are the primary source of nearly all tiller growth, yet understanding of fire and nitrogen effects on bud banks is limited. We tested effects of fire and nitrogen addition on bud banks of purple threeawn (Aristida purpurea Nutt.), a perennial C4 bunchgrass. Fire (no fire, summer fire, fall fire) and nitrogen addition (0, 46, 80 kg·ha-1) treatments were assigned in a completely randomized, fully factorial design and axillary buds were evaluated on two similar sites in southeastern Montana 1 and 2 years after fire. Permanently marked plants were assessed for live tiller production, and randomly selected tillers were sampled to determine active and dormant buds per tiller. Fire and nitrogen had opposite effects on axillary buds. Summer and fall fire reduced active buds by 42% relative to nonburned plots. Adding nitrogen at 46 or 80 kg·ha-1 increased active buds per tiller 60% compared with plots with no nitrogen addition. The number of dormant buds per tiller was similar across fire treatments and levels of nitrogen. Fire and nitrogen had interacting effects on total buds at the tiller level. Without nitrogen addition, fall and summer fire reduced total buds per tiller about 70%. Nitrogen had no effect on total buds per tiller for nonburned plants. However, total number of buds per tiller was greater with nitrogen addition following fall fire and increased with each increase in nitrogen following summer fire. Results indicate fire effectively controls purple threeawn through bud bank reduction and that nitrogen can stimulate bud production. Interacting effects of fire and nitrogen on buds reveal a potential source of inconsistency in nitrogen effects and a possible method of facilitating recovery of fire-sensitive bunchgrasses after fire.

Fire and nitrogen alter axillary bud number and activity in purple threeawn

Fire and nitrogen alter axillary bud number and activity in purple threeawn