Multiplication Rate Research Articles

Seed Yam Production Using High-Quality Minitubers Derived from Plants Established with Vine Cuttings

Yam (Dioscorea spp.) is a valuable food security crop in West Africa, where 92% of the world production occurs. The availability of quality seed tubers for increased productivity is a major challenge. In this study, minitubers weighing 1, 3, and 5 g produced from virus-free single-node vine cuttings of two improved yam varieties (Asiedu and Kpamyo) growing in an aeroponics system were assessed for suitability in seed production at a population of 100,000 plants ha−1. A 3 × 2 factorial experiment with randomized complete block design and three replications was set up during the cropping seasons of 2017 to 2019 at the International Institute of Tropical Agriculture Research Station in Kubwa, Abuja, Nigeria. Results showed field establishments of 87%–97.8%. Yields differed with minituber size, variety, and cropping season; the highest was 31.2 t ha−1 in 2019 and the lowest, 10 t ha−1 in 2018 from 5 and 1 g Kpamyo minitubers, respectively. The estimated number of tubers produced per hectare by 1, 3, and 5 g minitubers was 101,296, 112,592, and 130,555, with mean weights per stand of 159.2, 187.3, and 249.4 g, respectively. We recommend using less than 6 g minitubers for seed yam production due to their high multiplication rates.

Elicitation of phenylpropanoids in maqui (Aristotelia chilensis [Mol.] Stuntz) plants micropropagated in photomixotrophic temporary immersion bioreactors (TIBs)

A biotechnological system for the production of plants biomass and phenylpropanoids of maqui was developed in photomixotrophic TIBs. The in vitro maqui multiplication was evaluated using combinations of TDZ and BAP in TIBs 1L capacity. Treatment of MS basal supplemented with TDZ 1 mg/L shows the best results for the variables fresh weight and multiplication rate. Photomixotrophic conditions were standardized in media with 3%, 2%, 1%, 0% sucrose at a light intensity of 100 µM m−2 s−1. The treatments reduced in sucrose (1 and 2%) and air supplemented with 0.4 MPa CO2 do not differ significantly in biomass production (fresh weight per cluster of plants) compared to the control treatment with sucrose 3% and standard air. Treatment with ABA (1 m/l) induced the production and accumulation of phenylpropanoids metabolites in maqui cultures bioreactors. Phenylpropanoids in in vitro biomass of maqui and culture medium from TIBs were determined in parallel with control samples from wild plants and mature fruits. After the third day of analysis, not significant differences in polyphenols and anthocyanin contents were verified between the treatments of maqui in TIBs + ABA and controls. The non-significant differences in the contents of polyphenols and anthocyanin were maintained until the 15 days of analysis. The antioxidant capacity comparing samples of maqui in bioreactors and wild plants showed no significant differences by the ORAC test from day 5 to day 15 of the study. Results originate an optimized methodology that was scale to SETIS™ bioreactors of 5L capacity. For the first time maqui micropropagation has been established in TIBs followed by elicitation of phenylpropanoids metabolites. Contents of metabolites from maqui in TIBs do not differ from those of wild fruits, while antioxidant capacity of phenylpropanoids was preserved during the study.

Relative preference and demographic parameters of Encarsia formosa Gahan against Trialeurodes vaporariorum (Westwood)

BackgroundThe greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), is a cosmopolitan, polyphagous and a serious pest of vegetables and ornamentals in greenhouse. Encarsia formosa Gahan (Hymenoptera: Aphelinidae) is an important primary endoparasitoid species of the greenhouse whitefly.ResultsIn the present study, per cent parasitisation attained 50% on the 4th instar and 46% on the third 3rd instar of T. vaporariorum by E. formosa. The mean duration period of the parasitoid from egg to host mummification, mummification to adult emergence (pupal period) was 11 and 7.8 days on 3rd instar and 8.5 and 7.6 days on 4th instar, respectively. The total time period from egg to adult emergence reached 18.8 days on 3rd instar and 16.2 days on 4th instar. Longevity of the female parasitoids was 8.3 and 8.8 days on 3rd and 4th instars, respectively. The pre-ovipositional, ovipositional and post-ovipositional periods of the parasitoid were 1.2, 6.4 and 1.0 days on 3rd instar and 1.2, 6.7 and 1.0 days on 4th instar, respectively. The finite rate of natural increase (λ), doubling time and weekly multiplication rate of the 3rd instar was 1.16±0.002 times per day, 4.71±0.04 days and 2.80±0.03 folds, respectively and 1.17±0.002 times per day, 4.34±0.04 days and 3.06±0.03 folds for the 4th instar.ConclusionsStudies indicated that the 4th nymphal instar of the host was more suitable for parasitisation with E. formosa. The parasitoid species could be mass multiplied and utilised as a component of integrated pest management programme of T. vaporariorum after evaluation under field conditions.

Bulb Dormancy In Vitro-Fritillaria meleagris: Initiation, Release and Physiological Parameters.

In ornamental geophytes, conventional vegetative propagation is not economically feasible due to very slow development and ineffective methods. It can take several years until a new plant is formed and commercial profitability is achieved. Therefore, micropropagation techniques have been developed to increase the multiplication rate and thus shorten the multiplication and regeneration period. The majority of these techniques rely on the formation of new bulbs and their sprouting. Dormancy is one of the main limiting factors to speed up multiplication in vitro. Bulbous species have a period of bulb dormancy which enables them to survive unfavorable natural conditions. Bulbs grown in vitro also exhibit dormancy, which has to be overcome in order to allow sprouting of bulbs in the next vegetation period. During the period of dormancy, numerous physiological processes occur, many of which have not been elucidated yet. Understanding the process of dormancy will allow us to speed up and improve breeding of geophytes and thereby achieve economic profitability, which is very important for horticulture. This review focuses on recent findings in the area of bulb dormancy initiation and release in fritillaries, with particular emphasis on the effect of plant growth regulators and low-temperature pretreatment on dormancy release in relation to induction of antioxidative enzymes’ activity in vitro.

Higher gametocyte production and mosquito infectivity in chronic compared to incident Plasmodium falciparum infections

Plasmodium falciparum gametocyte kinetics and infectivity may differ between chronic and incident infections. In the current study, we assess parasite kinetics and infectivity to mosquitoes among children (aged 5–10 years) from Burkina Faso with (a) incident infections following parasite clearance (n = 48) and (b) chronic asymptomatic infections (n = 60). In the incident infection cohort, 92% (44/48) of children develop symptoms within 35 days, compared to 23% (14/60) in the chronic cohort. All individuals with chronic infection carried gametocytes or developed them during follow-up, whereas only 35% (17/48) in the incident cohort produce gametocytes before becoming symptomatic and receiving treatment. Parasite multiplication rate (PMR) and the relative abundance of ap2-g and gexp-5 transcripts are positively associated with gametocyte production. Antibody responses are higher and PMR lower in chronic infections. The presence of symptoms and sexual stage immune responses are associated with reductions in gametocyte infectivity to mosquitoes. We observe that most incident infections require treatment before the density of mature gametocytes is sufficient to infect mosquitoes. In contrast, chronic, asymptomatic infections represent a significant source of mosquito infections. Our observations support the notion that malaria transmission reduction may be expedited by enhanced case management, involving both symptom-screening and infection detection.

Biological and life table parameters of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) from five different geographical regions of India

Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) is one of the most widely distributed destructive pests of cruciferous crops which significantly decrease the quality and quantity of yield. In India, it is widely distributed wherever Cruciferous crops are grown. The damage is caused by the larvae which damage the leaves by mining and making holes. We studied the biological and growth rate parameters of this pest collected from five different geographical regions of India under laboratory conditions. Various biological parameters like total developmental period, oviposition period and adult longevity are found to be influenced by different geographical regions. Growth parameters like net reproductive rate, true generation time, true intrinsic rate of increase, finite rate of increase, doubling time and weekly multiplication rate of the pest also differed significantly among population from different geographical regions. The net reproductive rate was maximum for Hyderabad and Bengaluru population and minimum for Solan and Keylong population and the same was true for the intrinsic rate of increase. The finite rate of increase which is designated as the number of time, the population increases per unit time was 1.39, 1.36, 1.32, 1.25 and 1.20 for Bengaluru, Hyderabad, Ludhiana, Solan and Keylong population with multiplication rate of 2.98, 2.63, 2.14, 1.75 and 1.50 days, respectively and the difference was statistically significant. Further studies need to confirm the delineation of this pest in different geographical regions and accordingly the management strategies should be formulated for these regions.

Dynamic changes and multiplication rate of white blood cell count may direct the timing of cytoreduction chemotherapy during induction treatment in newly diagnosed acute promyelocytic leukemia with low-intermediate risk.

In order to explore the optimal timing for initiating cytoreduction chemotherapy following all-trans retinoic acid plus arsenic trioxide administration, 58 newly diagnosed patients with acute promyelocytic leukemia (APL) with low-intermediate mortality risk were retrospectively analyzed. During induction treatment, white blood cell (WBC) count >4x109/l and multiplication rate of WBC <3 days were defined as rapid WBC multiplication. Patients were divided into two groups: With or without rapid WBC multiplication. Comparison between the two groups revealed that the incidence of differentiation syndrome (DS) (48.1% vs. 6.5%; P<0.001), grade 3-4 bleeding (34.8% vs. 6.5%; P=0.022) and peak WBC count (30.4±20.0x109/l vs. 8.67±5.4x109/l; P<0.001) were significantly higher in the group with rapid WBC multiplication compared with in the group without rapid WBC multiplication. No significant differences were observed in bone marrow depression, infection, complete remission (CR) rate, time to achieve CR and early mortality rate between the two groups. Multivariate analysis revealed that WBC count at chemotherapy initiation was an independent risk factor for the occurrence of DS (P=0.040). Peak WBC count and rapid WBC multiplication were significantly associated with grade 3-4 bleeding (P=0.019 and P=0.002, respectively). Hence, WBC count at chemotherapy initiation along with its multiplication rate may direct the timing of cytoreduction chemotherapy during induction treatment in newly diagnosed APL with low-intermediate risk.

Development of robust in vitro culture protocol for the propagation of genetically and phytochemically stable plants of Withania somnifera (L.) Dunal (Ashwagandha)

Withania somnifera (L.) Dunal is an important medicinal plant that has gained a lot of attention since ancient times due to its immense pharmaceutical potential. Scientific validations of its therapeutic potential against many diseases have immensely increased its demand in the domestic and international market. Thus, to narrow down the huge gap between its demand and supply, alternative strategies to conventional cultivation are required. In vitro propagation system provides a feasible option for the production of large-scale healthy, genetically and phytochemically uniform W. somnifera plants to boost the herbal industry and facilitate pre-clinical studies. However, the major challenge in in vitro propagation of W. somnifera is to maintain a high rate of shoot multiplication for prolonged periods in cytokinin containing MS medium. In the current investigation, for prolonged maintenance of in vitro shoots, a multi-step protocol involving the rotational subculture of Withania shoots in the auxin-cytokinin containing culture medium has been developed to minimize the adverse effects of cytokinin. In vitro shoots after prolonged subculture were checked for genetic uniformity and stable pharmaceutically important constituents. Furthermore, in vitro rooting was initiated either in an auxin-dependent or auxin-independent manner through modulation of ammonium nitrate strength. Hence, the protocol developed for in vitro propagation of W. somnifera is cost-effective and can be efficiently used for the industrial production of withanolides.

An overview of multifaceted role of Trichoderma spp. for sustainable agriculture

The excessive use of chemical fertilizers and pesticides have caused several negative impacts on the environment and human health. They degrade soil fertility, build up resistance on pathogens, inhibit microbial activities and also enhance greenhouse gas emission. It is impossible and inappropriate to control plant pathogens by using chemical pesticides alone. Emphasize should be given towards organic fertilizers and pesticides to attain sustainability in agriculture. The use of Trichoderma is slowly increasing in the recent years among progressive farmers as an alternative to chemical fertilizers and pesticides. Slow rate of multiplication and colonization, susceptible to biotic and abiotic stresses, incomplete elimination of pathogens and high cost are the major problems behind its poor adoption among the farmers. To overcome these challenges different strains of Trichoderma should be identified which can multiply and colonize rapidly, least affected by environmental conditions and having wide host range on pathogens. In addition, farmers should be made aware about the importance of Trichoderma in agriculture through various extension facilities for its wide scale adoption. Trichoderma can be the viable and sustainable alternative which acts as biofertilizer, bioremediator and biocontrol agent. Nevertheless, the use of Trichoderma is limited on research activities and its application at farmers' level is not yet satisfactory. Thus, this study based on critical analysis of the research works from worldwide researchers aims to reveal the present scenario of the use of Trichoderma, its importance, modes of action, methods of application and multiplication, challenges for wide scale adoption and its appropriate solutions.

AgNO3 improved micropropagation and stimulate in vitro flowering of rose (Rosa x hybrida) cv. Sena

Abstract Rose is one of the most important cut flower in the world. Rose micropropagation was used for production of clonal and disease-free plantlets and to breeding purposes. However, many important rose cultivars showed physiological disorders as early-leaf senescence and very low multiplication rate under in vitro conditions. Our hypothesis is that these symptoms were associated with high sensibility of these cultivars to ethylene accumulation on in vitro environment. The rose cv. Sena was in vitro cultivated under different concentrations of AgNO3 and two light sources, LED and fluorescent lamps, as a way to investigate in vitro similar symptoms to ethylene accumulation. AgNO3 at 1.0-2.0 mg L-1 solved the main in vitro physiological disorders observed in this rose cultivar. Also, AgNO3 stimulated induction of 50% of rose shoots to in vitro flowering at 2.0 mg L-1. Higher concentrations also resulted in flowering induction, but with imperfect flower development.

In vitro micropropagation of wild rare plant Rhododendron ledebourii Pojark

Rhododendron ledebourii Pojark. is a highly decorative rare species of the flora of Siberia (Russia) and can be used as a source of biologically active substances, as well as in landscaping. We have optimized the in vitro propagation protocol for this species. Sterilization of annual shoots of field plants with 5% lysoformin-3000 provided 70% aseptic viable explants. The addition of 2 mg L−1 glycine to Anderson’s medium in combination with 8 mg L−1 2-isopentyladenine and 3 mg L−1 indolyl-3-acetic acid stimulated a high multiplication rate and active growth of axillary and adventitious shoots. The adaptation of regenerants in a hydroponic installation containing ¼ of the basic composition of macro- and microsalts according to Murashige and Skoog’s medium promoted the development of powerful roots for subsequent successful acclimatization to ex vitro conditions. This approach ensured the survival rate of 90% microplants.

Development and evaluation of a new Plasmodium falciparum 3D7 blood stage malaria cell bank for use in malaria volunteer infection studies

BackgroundNew anti-malarial therapeutics are required to counter the threat of increasing drug resistance. Malaria volunteer infection studies (VIS), particularly the induced blood stage malaria (IBSM) model, play a key role in accelerating anti-malarial drug development. Supply of the reference 3D7-V2 Plasmodium falciparum malaria cell bank (MCB) is limited. This study aimed to develop a new MCB, and compare the safety and infectivity of this MCB with the existing 3D7-V2 MCB, in a VIS. A second bank (3D7-V1) developed in 1995 was also evaluated.MethodsThe 3D7-V2 MCB was expanded in vitro using a bioreactor to produce a new MCB designated 3D7-MBE-008. This bank and 3D7-V1 were then evaluated using the IBSM model, where healthy participants were intravenously inoculated with blood-stage parasites. Participants were treated with artemether-lumefantrine when parasitaemia or clinical thresholds were reached. Safety, infectivity and parasite growth and clearance were evaluated.ResultsThe in vitro expansion of 3D7-V2 produced 200 vials of the 3D7-MBE-008 MCB, with a parasitaemia of 4.3%. This compares to 0.1% in the existing 3D7-V2 MCB, and < 0.01% in the 3D7-V1 MCB. All four participants (two per MCB) developed detectable P. falciparum infection after inoculation with approximately 2800 parasites. For the 3D7-MBE-008 MCB, the parasite multiplication rate of 48 h (PMR48) using non-linear mixed effects modelling was 34.6 (95% CI 18.5–64.6), similar to the parental 3D7-V2 line; parasitaemia in both participants exceeded 10,000/mL by day 8. Growth of the 3D7-V1 was slower (PMR48 of 11.5 [95% CI 8.5–15.6]), with parasitaemia exceeding 10,000 parasites/mL on days 10 and 8.5. Rapid parasite clearance followed artemether-lumefantrine treatment in all four participants, with clearance half-lives of 4.01 and 4.06 (weighted mean 4.04 [95% CI 3.61–4.57]) hours for 3D7-MBE-008 and 4.11 and 4.52 (weighted mean 4.31 [95% CI 4.16–4.47]) hours for 3D7-V1. A total of 59 adverse events occurred; most were of mild severity with three being severe in the 3D7-MBE-008 study.ConclusionThe safety, growth and clearance profiles of the expanded 3D7-MBE-008 MCB closely resemble that of its parent, indicating its suitability for future studies. Trial Registration: Australian New Zealand Clinical Trials registry numbers: P3487 (3D7-V1): ACTRN12619001085167. P3491 (3D7-MBE-008): ACTRN12619001079134

Micropropagation of pineapple (Ananas comosus L. Var. Smooth cayenne) in temporary immersion bioreactor system (TIPS)

Pineapple is an important edible fruit in the family Bromeliaceae popularly grown in the tropical and subtropical countries. Commercial prodution of pineapple requires large volume of planting materials which could not easily be obtained using conventional method of propagation. A protocol for mass propagation of pineapple (Ananas comosus L. var.smooth cayenne) using temporary immersion bioreactor system has been developed.The protocol involves four immersion cycles in Murashinge and Skoog (MS) media fortified with 1mg/L or 2mg/L 6-Benzylaminopurine (BAP) with or without 0.25g/L activated charcoal (AC). The highest multiplication rate (120 -130 plants/bottle) was obtained when media was fortified with 1mg/l or 2mg/L BAP alone. The presence of activated charcoal (AC) promoted root morphogenesis, resulting in significant increase in roots formation in BAP suplemented media. A combination of BAP with AC significantly increased the number of competent plants(20 – 30 plants/bottle) after four weeks of culture in temporary immersion system. The system is recommended for rapid and efficient micropropagation of pineapple.

Micropropagation of banana (Musa spp) using temporary immersion bioreactor system

Banana is an important crop in the tropics which possess the potential for commercial production in Nigeria. Large scale production requires large volume of planting materials which may be difficult to obtain using conventional methods of propagation. Temporary immersion bioreactor system (TIBs) is a cost effective method for micropropagation of plants. The present study was carried out to develop an efficient method for rapid multiplication of banana using temporary immersion bioreactor system (TIBs). Banana microshoots were regenerated from young suckers obtained from field grown plants using conventional plant tissue culture. Microshoots of 2cm length were used as explants for multiplication in temporary immersion bioreactor system. Ten (10) explants were cultured in bioreactor bottles containing Murashinge and Skoog (MS) liquid media supplemented with different concentrations of 6-bezylaminopurine (BAP) with or without 250mg/L Activated Charcoal (AC). Results showed that explants cultured in media supplemented with 2 mg/L or 1mg/L BAP without AC gave the highest shoot multiplication rate of 900% and 800%, respectively compared to hormone free media. Production of competent plants (plants ready for ex vitro establisment) were however, influenced by the presence of AC and the highest percentage of competent plants (80%) were produced when media was fortified with 1mg/L BAP+ 250mg AC. Regenerated plants were successfully established in the field and were morphologically normal and fertile.

Medium-term in vitro conservation of Castanea spp. hybrid clones

Phytophthora cinnamomi is a threat to chestnut fruit production. For improving resistance to this pathogen, a breeding program was implemented based on controlled crosses between Castanea species (Europe x Asia), using the latter as donor of resistant genes. The offspring with altered susceptibility to Phytophthora have been micropropagated. Plantlets were acclimatized to obtain copies of each genotype for phenotyping to Phytophthora susceptibility through inoculation tests. In this work, different methods of in vitro conservation, slow-growth storage and synthetic seed, during 9 and 12 months (at 4 oC, darkness) were compared. For slow-growth storage, different types and concentrations of carbon sources (sucrose and mannitol at 0.09, 0.16, 0.22 M) were compared. Conversely, for synseeds, nodal segments were encapsulated using different concentrations of Na-alginate (2.75, 3%) and released in a solution of CaCl22H2O (50, 75, 100 mM). For conservation, three conditions were tested: empty tubes; tubes filled (15 mL) with sterile distilled water, and tubes with a 30% glycerol solution. Both methods tested were found suitable for medium-term conservation (12 months). For slow-growth storage, the best results of survival (93.3%) and multiplication rate (2.10, at 2nd subculture) were achieved with 0.22 M sucrose. To the best of our knowledge, our studies show for the first time that the storage of the synseeds in tubes with sterile distilled water was the most effective method for conservation, allowing higher survival (97.5%) and germination (92.5%). The use of the highest concentration of Na-alginate demonstrated to promote the multiplication rate (3.18, at 2nd subculture).

Random walk through a fertile site.

We study the dynamics of random walks hopping on homogeneous hypercubic lattices and multiplying at a fertile site. In one and two dimensions, the total number N(t) of walkers grows exponentially at a Malthusian rate depending on the dimensionality and the multiplication rate μ at the fertile site. When d>d_{c}=2, the number of walkers may remain finite forever for any μ; it surely remains finite when μ≤μ_{d}. We determine μ_{d} and show that 〈N(t)〉 grows exponentially if μ>μ_{d}. The distribution of the total number of walkers remains broad when d≤2, and also when d>2 and μ>μ_{d}. We compute 〈N^{m}〉 explicitly for small m, and show how to determine higher moments. In the critical regime, 〈N〉 grows as sqrt[t] for d=3, t/lnt for d=4, and t for d>4. Higher moments grow anomalously, 〈N^{m}〉∼〈N〉^{2m-1}, in the critical regime; the growth is normal, 〈N^{m}〉∼〈N〉^{m}, in the exponential phase. The distribution of the number of walkers in the critical regime is asymptotically stationary and universal, viz., it is independent of the spatial dimension. Interactions between walkers may drastically change the behavior. For random walks with exclusion, if d>2, there is again a critical multiplication rate, above which 〈N(t)〉 grows linearly (not exponentially) in time; when d≤d_{c}=2, the leading behavior is independent on μ and 〈N(t)〉 exhibits a sublinear growth.

Effects of explant position and orientation, medium ph and nitrogen sources on micropropagation of blackberry

Composition of the medium and the explant origin are factors that interfere on success of micropropagation of Rubus species. For blackberry cultivar LochNess it was not investigated yet how the position and orientation of explant, pH levels and nitrogen source interfere on micropropagation. In this work, focused on the establishment of in vitro culture, variables were studied on R. fruticosus cv Loch Ness, such as the choice of the explants depending on their original position on the mother plant, pH level and nitrogen sources of the culture medium. For the first time in vitro on Rubus, the downward orientation (capogatto) of shoot tips explants was compared with the normal upward orientation. The highest weight and length values were recorded for the shoots proliferated from basal and nodal explants. For the initiation medium, the best multiplication rate were obtained in pH adjusted to 4.5. Shoot length was influenced by the nitrogen source; when associated with an increased light intensity, the complete substitution of ammonium by nitrate allowed results comparable with those obtained with the control medium containing both sources. The use of aminoacids did not improve the results. Apex orientation did not affect anatomical parameters or rooting rates of wild Rubus, but more efforts should be devoted on in vitro capogatto technique considering that advantages like reduction of plant growth regulators, cultivation on the same medium culture for more time and easily rooting can be established.

Are belowground clonal traits good predictors of ecosystem functioning in temperate grasslands?

Abstract In herbaceous communities which host many perennial species, belowground clonal organs and traits remain largely overlooked in ecosystem functioning studies. However, the belowground compartment is expected to play a key role as the greatest proportion of biomass is allocated belowground. Our main goal was to test whether including underexplored clonal traits (in tandem with widely used aboveground traits) improves the ability to predict biomass production and soil carbon in temperate grasslands. We examined the relationships between five plant functional traits (canopy height, specific leaf area [SLA], lateral spread, multiplication rate, persistence of rhizome) and biomass allocation (aboveground, roots, rhizomes) and soil organic carbon (SOC). We studied 52 grassland plots clustered in two Central European regions differing by management intensity. We assessed biomass allocated aboveground and belowground (into roots and rhizomes separately). SOC was measured from averaging five soil cores at each plot. Trait community means were calculated for each trait from species compositions using databases. The most important traits in predicting biomass allocation were canopy height and persistence of rhizome. Results, however, differed for the two regions implying context dependency of the relationships. Persistence of rhizome and canopy height emerged as traits largely affecting ecosystem functioning at the less intensively managed grasslands—likely because of their links to biomass production and plant economics spectrum. At the more intensively managed grasslands, canopy height and SLA were negatively correlated with root biomass, with persistence of rhizome playing a (lesser) role. We found no significant predictors for SOC. Synthesis. This study is the first attempt to integrate belowground clonal and aboveground traits to predict biomass allocation and soil carbon. Findings indicate that the ability of plant functional traits in predicting ecosystem functioning is highly context dependent, varying greatly even within the same community type. Only SLA and, to a lesser extent, persistence of rhizome consistently predicted root biomass in the two regions. We call for a broader implementation of the whole‐plant multifunctional approach applied here, ideally extending to other open ecosystems. A free Plain Language Summary can be found within the Supporting Information of this article.

DKW basal salts improve micropropagation and callogenesis compared with MS basal salts in multiple commercial cultivars ofCannabis sativa

Existing Cannabis sativa micropropagation protocols use a limited number of cultivars and the results are often not reproducible. Currently, Murashige and Skoog basal salt mixture (MS) + 0.5 μmol/L thidiazuron (TDZ) has been reported as the optimal medium for nodal micropropagation, yet our preliminary studies with this medium have resulted in abnormal morphology and high mortality rates in multiple cultivars. Following an initial screen of basal salt mixtures [MS, B5, BABI, and Driver–Kuniyaki–Walnut (DKW)], we determined that DKW produced the healthiest plants. In a second experiment, the multiplication rate and canopy area of explants grown on MS + 0.5 μmol/L TDZ and DKW + 0.5 μmol/L TDZ were compared using five drug-type cultivars. The combined multiplication average of explants grown on DKW + 0.5 μmol/L TDZ was 1.5× higher than explants grown on MS + 0.5 μmol/L TDZ. Similarly, the combined average of the canopy area was twice as large on DKW + 0.5 μmol/L TDZ. In the third experiment, callogenesis was compared using a concentration range of 2,4-dichlorophenoxyacetic acid (0–30 μmol/L) on both MS and DKW, and similarly, callus growth was superior on DKW. This study presents the largest comparison of basal salt compositions on the micropropagation of five commercially grown Cannabis cultivars to date.

Role of human Pegivirus infections in whole Plasmodium falciparum sporozoite vaccination and controlled human malaria infection in African volunteers

BackgroundDiverse vaccination outcomes and protection levels among different populations pose a serious challenge to the development of an effective malaria vaccine. Co-infections are among many factors associated with immune dysfunction and sub-optimal vaccination outcomes. Chronic, asymptomatic viral infections can contribute to the modulation of vaccine efficacy through various mechanisms. Human Pegivirus-1 (HPgV-1) persists in immune cells thereby potentially modulating immune responses. We investigated whether Pegivirus infection influences vaccine-induced responses and protection in African volunteers undergoing whole P. falciparum sporozoites-based malaria vaccination and controlled human malaria infections (CHMI).MethodsHPgV-1 prevalence was quantified by RT-qPCR in plasma samples of 96 individuals before, post vaccination with PfSPZ Vaccine and after CHMI in cohorts from Tanzania and Equatorial Guinea. The impact of HPgV-1 infection was evaluated on (1) systemic cytokine and chemokine levels measured by Luminex, (2) PfCSP-specific antibody titers quantified by ELISA, (3) asexual blood-stage parasitemia pre-patent periods and parasite multiplication rates, (4) HPgV-1 RNA levels upon asexual blood-stage parasitemia induced by CHMI.ResultsThe prevalence of HPgV-1 was 29.2% (28/96) and sequence analysis of the 5′ UTR and E2 regions revealed the predominance of genotypes 1, 2 and 5. HPgV-1 infection was associated with elevated systemic levels of IL-2 and IL-17A. Comparable vaccine-induced anti-PfCSP antibody titers, asexual blood-stage multiplication rates and pre-patent periods were observed in HPgV-1 positive and negative individuals. However, a tendency for higher protection levels was detected in the HPgV-1 positive group (62.5%) compared to the negative one (51.6%) following CHMI. HPgV-1 viremia levels were not significantly altered after CHMI.ConclusionsHPgV-1 infection did not alter PfSPZ Vaccine elicited levels of PfCSP-specific antibody responses and parasite multiplication rates. Ongoing HPgV-1 infection appears to improve to some degree protection against CHMI in PfSPZ-vaccinated individuals. This is likely through modulation of immune system activation and systemic cytokines as higher levels of IL-2 and IL17A were observed in HPgV-1 infected individuals. CHMI is safe and well tolerated in HPgV-1 infected individuals. Identification of cell types and mechanisms of both silent and productive infection in individuals will help to unravel the biology of this widely present but largely under-researched virus.