The Role of Growth Regulators in The Multiplication of Stevia Rebaudiana Bertoni Shoot and Callus Induction in Vitro

The research was conducted to investigate the effect of plant growth regulators on the vegetative multiplication of the Stevia plant shoot and the induction of callus from it. The results indicated that the interaction between 2.0 mg. L-1 BA with 0.5 mg. L -1 Kin gave the highest rate number of shoot with 6.32 branches and the highest average of leaves number Were 9.60 leaves compared to the lowest average for the number of shoot and leaves Were 1.40 shoot and 3.80 leaves respectively. As for the length of the shoot, the interaction between (1.0 mg. L-1 BA and 0.5 mg. L-1 Kin) gave the highest average shoot length 4.31 cm compared to the control which gave 2.20 cm. in connection with the callus induction, the concentration 3 mg. L-1 of NAA gave the highest percentage of callus induction from leaves 100%, and the lowest mean of days that for callus initiation was 9 days compared to the control which reached to 20 days. As for the wet and dry weights of callus tissue, the interaction between 2.0 mg. L-1 NAA and 0.5 mg. L -1BA gave the highest wet weight rate 3.68 g and the average dry weight was 0.31 g compared to the control which gave the lowest rate 0.95 g, 0.08 g respectively.

A fast and effective protocol for obtaining genetically diverse stevia (Stevia rebaudiana Bertoni) regenerants through indirect organogenesis

Plant regeneration through indirect organogenesis allows obtaining genetic variability that can be used in the creation of new cultivars. The study presents a fast and effective protocol of one-step preparation of stevia (Stevia rebaudiana Bertoni) regenerants. To obtain callus tissue and shoot regeneration, leaves and nodal segments were used as primary explants, which were placed on MS (Murashige and Skoog) medium supplemented with plant growth regulators (PGRs): NAA (1-naphthaleneacetic acid – 2.0 mg·dm–3, BA (6-benzylaminopurine – 4.0 mg·dm–3), 2,4‑D (2,4-dichlorophenoxyacetic – 2.0 mg·dm–3). Callus tissue was formed on both types of explants, however, only those derived from nodal segments were proliferating. An average of 3.92 shoots per explant were obtained from leaf explants on the applied medium after 6 weeks of culture. The analysis of the morphogenetic capacity of the obtained regenerants was carried out on MS medium supplemented with PGRs – kinetin (0.25 mg·dm–3), BA (0.5 mg·dm–3). The evaluation of the mean number of shoots, mean shoot length (cm), and the mean number of nodes per shoot indicated phenotypic variability of regenerants. The use of RAPD (randomly amplified polymorphic DNA) markers confirmed the differences also at the DNA level. The proposed one-step indirect organogenesis regeneration protocol induced somaclonal variation of Stevia rebaudiana Bertoni and the obtained regenerants, after selection, could be used in the breeding of this species.

Obtaining Salt Stress-Tolerant Eggplant Somaclonal Variants from In Vitro Selection

An efficient regeneration protocol was applied to regenerate shoots on salt stress-tolerant calli lines of aubergine (Solanum melongena). These NaCl-tolerant cell lines were obtained by two different methods. On the one hand, the developed callus tissue was transferred to a medium with a continuous salt content of 40, 80, 120, or 160 mM NaCl. On the other hand, the callus tissue was subjected to a stepwise increasing salinity to 160 mM NaCl every 30 days. With the second method, calli which could be selected were characterized by compact growth, a greenish color, and absence of necrotic zones. When grown on salt-free medium again, NaCl-tolerant calli showed a decline in relative growth rate and water content in comparison to the control line. This was more obvious in the 120 mM NaCl-tolerant callus. Lipid peroxidase activity increased in 40 and 80 mM NaCl-tolerant calli; yet did not increase further in 120 mM-tolerant callus. An increase in ascorbic acid content was observed in 80 and 120 mM NaCl-tolerant calli compared to the 40 mM NaCl-tolerant lines, in which ascorbic acid content was twice that of the control. All NaCl-tolerant lines showed significantly higher superoxide dismutase (SOD) (208–305–370 µmol min−1 mg−1 FW) and catalase (CAT) (136–211–238 µmol min−1 mg−1 FW) activities compared to control plants (231 and 126 µmol min−1 mg−1 FW). Plants were regenerated on the calli lines that could tolerate up to 120 mM NaCl. From the 32 plants tested in vitro, ten plants with a higher number of leaves and root length could be selected for further evaluation in the field. Their high salt tolerance was evident by their more elevated fresh and dry weight, their more increased relative water content, and a higher number and weight of fruits compared to the wild-type parental control. The presented work shows that somaclonal variation can be efficiently used to develop salt-tolerant mutants.

Effects of Phytophthora Inoculations on Photosynthetic Behaviour and Induced Defence Responses of Plant Volatiles in Field-Grown Hybrid Poplar Tolerant to Bark Canker Disease

Bark cankers accompanied by symptoms of decline and dieback are the result of a destructive disease caused by Phytophthora infections in woody plants. Pathogenicity, gas exchange, chlorophyll a fluorescence, and volatile responses to P. cactorum and P. plurivora inoculations were studied in field-grown 10-year-old hybrid poplar plants. The most stressful effects of P. cactorum on photosynthetic behaviour were found at days 30 and 38 post-inoculation (p.-i.), whereas major disturbances induced by P. plurivora were identified at day 30 p.-i. and also belatedly at day 52 p.-i. The spectrum of volatile organic compounds emitted at day 98 p.-i. was richer than that at day 9 p.-i, and the emissions of both sesquiterpenes α-cubebene and germacrene D were induced solely by the Phytophthora inoculations. Significant positive relationships were found between both the axial and the tangential development of bark cankers and the emissions of α-cubebene and β-caryophyllene, respectively. These results show that both α-cubebene and germacrene D are signal molecules for the suppression of Phytophthora hyphae spread from necrotic sites of the bark to healthy living tissues. Four years following inoculations, for the majority of the inoculated plants, the callus tissue had already closed over the bark cankers.

Stand-Alone Rod Augmentation for Instrumentation Failure after Pedicle Subtraction Osteotomy: A Case Report with a 2-year Follow-up

Background: Revision surgery of spine can be a complex procedure and has known complications. It involves hardware revision, removal of scar/callus tissue, realignment of sagittal balance, and anterior augmentation. However, through this report, we aim to demonstrate that a stand-alone rod augmentation at the failure site without removal of scar/callus tissue and/or anterior fixation can achieve excellent results in select cases. Case Report: A 66-year-old woman underwent L2 pedicle subtraction osteotomy (PSO) + T9-iliac fixation for fixed sagittal imbalance and osteoporotic collapse of L3. One year later, she developed progressive axial lumbar pain and difficulty in mobilization. The patient was diagnosed with pseudoarthrosis and instrumentation failure and underwent revision spine surgery with stand-alone rod augmentation. She had anuneventful rehabilitation and showed complete radiographic union and excellent clinical outcome in the 2-year follow-up. Conclusion: Stand-alone rod augmentation can provide stable posterior construct to prevent future pseudoarthrosis and/or instrumentation failure after revision spine surgery in selected cases. Anterior augmentation or resection dural scar tissue or dissection through callus tissue is not always necessary.

Periwound skin care considerations for older adults

This article discusses the effects of ageing on the skin, particularly the main structural and functional changes that occur in the epidermis and dermis that make the skin more vulnerable to damage. Specific alterations that occur with ageing include slower epidermal turnover, flattening of the epidermal-dermal junction, loss of moisture and hydration as well as reduced immunity placing the skin at increased risk of damage. The discussion will also examine common periwound complications associated with ageing including; maceration, excoriation, dry skin, hyperkeratosis, callus, contact dermatitis and eczema. Strategies to manage these problems and interventions to reduce the risk of these complications include moisturising the skin to make it more resilient, debriding keratinised and callus tissue in the periwound area, appropriate choice of dressings to manage excessive exudate, careful removal of dressings as well as treating inflammatory conditions of the periwound skin.

Macroscopic and Microscopic Modifications of Wood after Debarking of Trees in the South Cameroon

Wounding of trees by debarking has been reported to form a callus tissue. This work aims to investigate macroscopic and microscopic modifications of wood after the removal of barks in Alstonia boonei, Scorodophloeus zenkeri, and Garcinia lucida. Species that are not yet barking were wounded to conducting experimental debarking. The wound was rectangular with 30 cm vertically with a lateral extent of 10 cm. Every three months, there was a follow-up for fifteen months during which the macroscopic and microscopic phenomena were observed and recorded. Microsections of 15–20 μm thickness were taken on a piece of wood from the regenerated and intact wood, with a sledge microtome. Staining of cell walls was done with safranin and fast green to increase contrast in an anatomical slide. Analyzes of the variability of xylem anatomical features were done by semi-automatic measurements using the SpectrumSee digital image analysis software. The speed of recovery of the bark of these three species is 9.04 cm/year for A. boonei, 5.9 cm/year for S. zenkeri, and 3.85 cm/year for G. lucida. The recovery of A. boonei’s bark is the fastest, and it just takes 15 months to heal its wound. Densities of vessels were 8, 38, and 17 per mm², respectively, for the wood of A. boonei, S. zenkeri, and G. lucida before barking. These values increased for A. boonei (26) and G. lucida (20) except for S. zenkeri (25). In all species, the diameter of the vessels has decreased in the regenerated wood. Management practices that enhance the monitoring of sustainable harvesting levels of species and promote alternative plants for the same uses should be considered as part of conservation strategies.

Colonization of Trees by Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) Is Influenced by Duration of Flood Stress

The ambrosia beetles Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) bore into flood-stressed trees to establish colonies, but the influence of flooding duration on colonization is unknown. This relationship was examined by flooding trees for various time periods and evaluating colonization. In one experiment, X. germanus bored into 20 dogwood (Cornus florida L.) trees during a 3-d flood treatment. Ten trees dissected that season had no offspring present in tunnels; the remaining trees appeared healthy and bloomed the following spring. In another experiment, dogwood trees were flooded for 3 or 7 d and then dissected to assess colonization. The incidence of superficial (short unbranched) and healed (callus tissue in entrance) tunnels was greater in the 3-d trees, while the incidence of tunnels with X. germanus or offspring was greater in the 7-d trees. Four experiments (three in Ohio and one in Virginia) had flood treatments of 0 (nonflooded), 3, 5, 7, and 10 d. Numbers of tunnel entrances, tunnels with X. germanus, and incidence of tunnels with offspring or live foundresses tended to increase as flood duration increased on apple (Malus × domestica Borkh.), dogwood, and redbud (Cercis canadensis L.) in Ohio and redbud in Virginia. Nonflooded trees in Ohio had no boring activity, but ambrosia beetles bored into three nonflooded trees in Virginia. Indicators of unsuccessful colonization, such as superficial tunnels and healing, decreased as flood duration increased. These results suggest tree crops may recover from boring by ambrosia beetles following short-duration flood events, and not necessarily require culling.

Tissue Oxygenation Measurements to Aid Scalpel Debridement Removal in Patients with Diabetes

Background: Callus formation in the diabetic foot increases the risk of ulcer onset. It is standard procedure to remove these dead tissue layers to reduce rising pressures. In a surgical procedure known as scalpel debridement, or chiropody the callus tissue is removed up to the epidermal layer. Factors may influence the outcome of this surgical process such as clinician inexperience. In an effort to standardize the debridement process, tissue oxygenation (TO) measurements are obtained before and after to study the effect of debridement on callus tissue. Methods: Fifteen debridement cases were analyzed using near infrared (NIR) imaging to study changes in TO. The NIR-based device used in this study estimates effective changes in TO in terms of oxy-, deoxy-, total hemoglobin, and oxygen saturation. Weber contrasts between callus tissue and the surrounding normal tissue were compared following debridement for all TO parameters. In a secondary analysis, callus tissue was segmented into quadrants and a percent of significance (in terms of total TO change) was calculated using a t-test. Results: Results show majority of cases displayed greater than 80% as the significant change in TO following debridement, except in cases with the presence of blood clot (a common precursor for ulceration). In cases where incomplete debridement was suspected, a significant change in TO was still observed. Conclusions: With extensive systematic studies in the future, NIR imaging technique to measure changes in TO may be implemented as a low-cost hand-held imaging device useful for objectively assessing the effectiveness of the scalpel debridement process.

Introduction of hyssopus officinalis l . into in vitro culture to optimize the conditions for obtaining callus tissues and microclonal propagation as a promising metod of innovative agrobiotechnologies

The sterilization process of plant explants of H. officinalis was optimized when introduced into an in vitro culture, the most effective sterilization modes, optimal sterilizing agents, their exposure time and concentration were selected. Callus tissues and mini-plants of H. officinalis were obtained in vitro and the most optimal nutrient media were determined both for microclonal propagation and for the induction of callus tissue H. officinalis, which can be further used for mass cultivation of cell and culture and obtaining safe bio-additives with active substances for livestock and crop production as a part of the development of modern agrobiotechnologies.