Establishment of Tissue Culture System of Actinidia deliciosa Cultivar “Guichang”

In order to breed virus-free plantlets of the kiwifruit cultivar “Guichang,” which belongs to Actinidia deliciosa, in this study, stem segments with buds were used as explants, the establishment of a tissue culture rapid propagation system was carried out, and then the virus status of tissue culture plantlets was detected via the real-time reverse transcription-polymerase chain reaction (RT-qPCR) method. The tissue culture rapid propagation system proved that the contamination and browning rates could be controlled below 20% and the survival rate could be exceeded by 70% when the single bud stem segment of “Guichang” kiwifruit was sterilized with 70% alcohol for 30–60 s and 15% NaClO for 15 min, respectively. Meanwhile, we screened the hormone concentration to get better results, and the appropriate medium for adventitious bud induction was MS + 6-BA (1.0 mg/L) + IBA (0.2 mg/L); for proliferation, it was MS + 6-BA (1.0 mg/L) + IBA (0.1 mg/L); and for rooting, it was 1/2 MS + IBA (0.3 mg/L), and the efficiency of induction, proliferation, and rooting could reach 74.07%, 79.63%, and 85.18%, respectively. In addition, the RT-qPCR results demonstrated that the infection rate of 9 viruses: apple stem grooving virus (ASGV), cucumber mosaic virus (CMV), Actinidia virus X (AVX), cucumber necrosis virus (CNV), ribgrass mosaic virus (RMV), citrus leaf blotch virus (CLBV), Actinidia virus B (AcVB), Pelargonium zonate spot virus (PZSV), and cherry leaf roll virus (CLRV) in the “Guichang” kiwifruit tissue culture plantlets was 0. This study could lay a foundation for the production of “Guichang” kiwifruit tissue culture seedlings, and the medium formula provided in this study was useful for the industrial rapid propagation of “Guichang” plantlets.

Multiple shoot induction and regeneration of Vanilla borneensis Rolfe - a critically endangered orchid of Assam, India

In the present investigation, a micropropagation protocol has been developed for Vanilla borneensis Rolfe – a critically endangered orchid through multiple shoot regeneration. Through in vitro multiple shoot regeneration from both nodal and shoot tip explants, maximum (100%) shoot induction was observed. The minimum time required for shoot bud induction was observed from the shoot tip (5–7 days) on medium supplemented with BAP (4.44 mM) + KIN (2.32 mM) as compared to the nodal explants. Maximum multiple shoot regeneration was observed from nodal explants on the medium supplemented with BAP (4.44 mM) + TDZ (6.82 mM). However, maximum shoot length was observed on the medium supplemented with BAP (4.44 mM) + 15% CW and the number of nodes (5.27±0.33) per shoot after 90 days. Maximum (80-100%) of root initiation was observed in almost all the concentrations of NAA. The shortest time of root initiation was found on the medium supplemented with NAA (5.37 mM). Further, acclimatization period was found to be 15 days with 70% acclimatization while 60% of survivability was observed in the field condition. This efficient micropropagation method of V. borneensis could be successfully used for mass propagation as well as conservation of the critically endangered wild orchid.

Micropropagation of Rare Scutellaria havanensis Jacq. and Preliminary Studies on Antioxidant Capacity and Anti-Cancer Potential

We report the development of in vitro propagation protocols through an adventitious shoot induction pathway for a rare and medicinal Scutellaria havanensis. In vitro propagation studies using nodal explants showed MS medium supplemented with 10 µM 6-Benzylaminopurine induced the highest number of adventitious shoots in a time-dependent manner. A ten-day incubation was optimum for shoot bud induction as longer exposures resulted in hyperhydricity of the explants and shoots induced. We also report preliminary evidence of Agrobacterium tumefaciens EHA105-mediated gene transfer transiently expressing the green fluorescent protein in this species. Transformation studies exhibited amenability of various explant tissues, internode being the most receptive. As the plant has medicinal value, research was carried out to evaluate its potential antioxidant capacity and the efficacy of methanolic leaf extracts in curbing the viability of human colorectal cancer cell line HCT116. Comparative total polyphenol and flavonoid content measurement of fresh and air-dried leaf extract revealed that the fresh leaf extracts contain higher total polyphenol and flavonoid content. The HCT 116 cell viability was assessed by colorimetric assay using a 3-(4,5-dimethyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide, showed a steady growth inhibition after 24 h of incubation. Scanning electron microscopy of leaf surface revealed a high density of glandular and non-glandular trichomes. This research provides a basis for the conservation of this rare plant and future phytochemical screening and clinical research.

Effect of light quality and extended photoperiod on flower bud induction during transplant production of day-neutral strawberry cultivars.

Day-neutral (DN) strawberry cultivars are increasingly grown in Canada because they produce flowers and fruits continuously until October. Appropriate artificial lighting conditions during preparation of high-quality transplants is critical. Unfortunately, systematic evaluation of appropriate artificial lighting conditions during transplant production is limited. The objective of this study was to determine how an extended photoperiod supplemented with different light quality affects the vegetative and reproductive growth of a day-neutral cultivar during transplant production. In the first trial, we investigated the photoperiodic nature of the DN cultivar ‘Albion’ under low intensity incandescent light. Transplants were grown under three light combinations with different far-red : blue ratios (1:5, 5:1 and 1:1), supplemented for long day (LD; 24h), short day (SD; 10h) photoperiods and during a night interruption (NI) for 2h. ‘Albion’ cultivar exhibited similar degree of flowering sensitivity regardless of photoperiod duration when incandescent light was used as predominant light source. In case of light emitting diodes (LEDs), dominant blue (1:5) LEDs prompted a significant increase in flower bud induction (FBI), more explicitly under the LD photoperiod. Furthermore, transplants grown under dominant blue light (1:5) supplied during NI produced 8 flower buds per plant, the highest among all treatments, and promoted flower development outside the crown. Based on the results, it appears that lower wavelengths advance flowering and higher wavelengths contribute towards the morphological traits especially during transplant production. Results suggest that combination of far-red and blue LEDs at 1:5 ratio could be a potential light source to improve flower bud induction and floral development to subsequently increase fruit production.

Micropropagation of Rare Scutellaria Havanensis Jacq. And Preliminary Studies on Antioxidant Capacity and Anti-cancer Potential

We report the development of in vitro propagation protocols through adventitious shoot induction pathway for a rare and medicinal Scutellaria havanensis. In vitro propagation studies using nodal explants showed MS medium supplemented with 10µM 6-Benzylaminopurine induced highest number of adventitious shoots in a time dependent manner. A ten - day incubation was optimum for shoot bud induction as longer exposures resulted in hyperhydricity of the explants and shoots induced. We also report preliminary evidence of Agrobacterium tumefaciens EHA105 - mediated gene transfer transiently expressing of green fluorescent protein in this species. Transformation studies exhibited amenability of various explant tissues, internode being the most receptive. As the plant has medicinal value, research was carried out to evaluate its potential antioxidant capacity and the efficacy of methanolic leaf extracts in curbing the viability of human colorectal cancer cell line HCT116. Comparative total polyphenol, and flavonoid content measurement of fresh and air dried leaf extract revealed that the fresh leaf extracts contain higher total polyphenol and flavonoid content. The HCT 116 cell viability assessed by colorimetric assay using a 3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide, showed a steady growth inhibition after 24 hours of incubation. Scanning Electron Microscopy of leaf surface revealed high density of glandular and non-glandular trichomes. This research provides basis for the conservation of this rare plant and future phytochemical screening and clinical research.

Acacia Mangium × A. Auriculiformis Micropropagation in a Non-Sterile Environment

Background: Autoclaving is used to eliminate contamination during tissue culturing, however, it is a complicated process, time-consuming and costly. Chemical sterilization of tissue culture can effectively eliminate contamination, is a simple procedure, and cost effective. However, studies on the chemical sterilization mostly focus on bud induction, while the effects of chemical sterilization overall process of tissue culture, including bud induction, proliferation, and rooting, remain to be determined. Here, we investigate the effect of chemical sterilization on bud induction, proliferation, and rooting of Acacia mangium × A. auriculiformis.Results: The results showed that chlorothalonil (0.2 g/L) was a suitable chemical sterilant, and bud induction medium was 1/8 Murashige and Skoog medium + agar 7 g/L + chlorothalonil 0.2 g/L + 6-benzylaminopurine 0.5 mg/L The highest induction rate (99.54%) was observed in the third to fifth buds’ stem segments collected in October treated with 0.8 g/L carbendazim for 3 min, with a contamination rate of 0. The rooting medium was agar 7 g/L + chlorothalonil 0.2 g/L+ indolebutyric acid 1.5 mg/L + naphthylacetic acid 0.5 mg/L, and the rooting rate was 97.62%. The proliferation rate and subculture duration showed a positive correlation, while the proliferation rate was 3.58 times higher at the fourth subculture rooting. Conclusions: Our results suggest that chlorothalonil can effectively replace autoclaving during bud induction, proliferation, and rooting of A. mangium × A. auriculiformis. The findings of this study provide technical support for rapid seedlings propagation, accelerates the breeding process of Acacia, and can be applied in other tree species.

Introduction pages

Notulae Botanicae Horti Agrobotanici Cluj-Napoca (NBHA): The papers published in Issue 2, Volume 49, 2021 represent new exciting researches in different topics of life science, respectively in plant science, horticulture, agronomy and crop science. Among the interesting articles we invite you to find news about: Genome-wide identification of WD40 superfamily genes and prediction of WD40 gene of flavonoid-related genes in Ginkgo biloba; Evaluation of mitotic activity in tapetal cells of grapevine (Vitis L.); Light-emitting diode spectra modify nutritional status, physiological response, and secondary metabolites in Ficus hirta and Alpinia oxyphylla; Plant growth-promoting rhizobacteria associated to candelilla rhizosphere (Euphorbia antisyphilitica) and its effects on Arabidopsis thaliana seedlings; Agronomical, physiological and molecular evaluation reveals superior salt-tolerance in bread wheat through salt-induced priming approach; Temperature-mediated shifts in chlorophyll biosynthesis in leaves of chlorophyll b-lacking rice (Oryza sativa L.); Basal stem cluster bud induction and efficient regeneration for the Tibetan endemic medicinal plant Swertia conaensis; A proposal for modifying coppicing geometry in order to reduce soil erosion in the forest areas; Exploring mycorrhizal fungi in walnut with a focus on physiological roles; Advance in mechanism of plant leaf colour mutation, etc. The Impact Factor communicated by ISI Clarivate (June 30, 2021), is IF 2020 = 1.444 (position 157 of 235 journals, Q3 in Plant Sciences). The metrics in Scopus – Elsevier (June 2, 2021): CiteScore 1.7 (#40/86 in Horticulture). ---------------------------------------------------------------------------------- Announcement From Volume 49, Issue 1, 2021, Notulae Botanicae Horti Agrobotanici Cluj-Napoca journal uses article numbers in place of the traditional method of continuous pagination through the volume. This step helps us to maintain a rapid, efficient production process by being able to define pagination as soon as a paper is accepted. For papers that use article numbers, the page number of full-text articles will start from 1 to the last page and the citation needs only to list the article number. The journal will continue to appear quarterly, as before, with four annual numbers (see Publication Frequency).

Basal stem cluster bud induction and efficient regeneration for the Tibetan endemic medicinal plant Swertia conaensis

The artificial rapid propagation system for Swertia conaensis T. N. Ho et S. W. Liu was explored to screen the appropriate plant regeneration method and to provide an efficient propagation mode, useful for artificial breeding technology or for further research and development of the Tibetan endemic medicinal plant. In this study, the most suitable explant and hormone were chosen according to single factor test. Next, the effects of different hormone combinations on basal stem cluster bud induction, callus induction, adventitious bud occurrence and plant regeneration were investigated by using complete combination and orthogonal experiment. The obtained results showed that the explants suitable for in vitro of S. conaensis were stem tips with leaves, which were regenerated through the method of basal stem cluster bud occurrence in the MS medium with 2.0 mg∙L-1 6-BA, 0.5 mg∙L-1 NAA, but the proliferation coefficient was low, only 3.16 after 40 days of culture. Subsequently, the proliferation coefficient failed to improve, irrespective of change of the concentration ratio of 6-BA and NAA. Therefore, in the orthogonal experiment of adding ZT, the MS medium with 1.0 mg∙L-1 ZT, 0.5 mg∙L-1 NAA and 2.5 mg∙L-1 6-BA induced a large number of callus green and compact, with 86.30% callus occurrence rate. After 40 days of culture, the rate of adventitious bud occurrence was 96.55% and the proliferation coefficient was high (10.37). The rooting rate was 100% in the 1/2MS medium with 0.5 mg∙L-1 NAA. The survival rate of regenerated plants was more than 95%. Indirect organogenesis was more efficient than direct organogenesis in in vitro culture of S. conaensis. In this study, the efficient and stable regeneration system of S. conaensis was achieved through the method of explant to callus to adventitious buds, which provided an effective way to an endangered species.

Review on the ecophysiology of important Andean fruits: Passiflora L.

The development of Andean fruit crops is viewed as an important and healthy contribution to global food consumption but ecophysiological studies on these fruit trees are scarce. 96% of approximately 520 Passiflora L. species are distributed in the Americas, especially in Colombia and Brazil. Many of these species originated on the edges of humid forests in tropical valleys. The four species: yellow passion fruit (Passiflora edulis f. flavicarpa Degener), sweet granadilla (Passiflora ligularis Juss.), purple passion fruit (Passiflora edulis f. edulis Sims) and banana passion fruit (Passiflora tripartita var. mollissima (Kunth) Holm-Niels & P.M. Jørg) are widely cultivated in Colombia, and their ecophysiological findings are described in this review. The demands, in terms of temperature (°C) and altitude (masl) are, for yellow passion fruits: 15-28 °C and 0-1,300 masl; sweet granadillas: 15-23 °C and 1,800-2,600 masl; purple passion fruits: 15-22/12-14 °C (day/night) and 1,600-2,300 masl; and banana passion fruit: 13-16 °C and 1.800-3.200 masl; all of them have high requirements for solar radiation, a minimum of 7 h of sunshine per day, to encourage flowering and fruit quality. Cloudy days decrease growth, flower bud induction and flower opening. Temperature and photosynthetic active radiation are the climatic factors that have the greatest effect on plant development. Relative humidity between 60 and 80% supports effective pollination and fecundation. Passiflora L. crops do not support long periods of waterlogging, with a maximum of 4 days for yellow passion fruit. Climatic events such as prolonged rain, intense droughts, strong winds and hail are harmful for these plants.