Germination and seedlings growth of domestic poppy (Papaver somniferum L.) regarding salinity and temperatures

In this research there were studied the effects of NaCl-induced salinity and environment temperatures on germination and seedlings growth of domestic poppy. The study was conducted in the controlled conditions in the plant growth chamber. There were applied different concentrations of NaCl (0 mM (control), 50 mM, 100 mM and 150 mM) and environment temperatures (10°C, 15°C and 20°C). The 50 seeds of domestic poppy cultivar (Detkovac) were sown in 4 replicates on the filter paper. The germination energy was determined on the 5th day and total germination rate and seedlings morphological characteristic were determined on the 10th day. At the 5th day germination energy was on average 28%. It was interesting to note that at the 10°C there were no germinated seeds after 5 days at all salinity treatments and also, at the salinity level of 150 mM NaCl at every temperature. The average germination rate (on 10th day) of domestic poppy seeds were 52% and it varied from 30% (150 mM NaCl and 20°C) to 90% (0 mM NaCl and 15°C). Different salinity of water solution had a very significant (p<0.01) influence on stem, root and total length (cm) of seedlings. The average root length was 1.3 cm and it varied from 0.9 cm (100 mM NaCl) to 1.8 cm (0 NaCl). The average stem length was 1.8 cm. The longest stem was found at control (2.7 cm), and between 50 and 100 mM of NaCl the difference was not significant and stem length averaged 1.4 to 1.3 cm depending on the temperature. Average total poppy seedlings length of this study was 3.0 cm and it varied from 4.5 cm at the control to 2.3 cm at 100 mM NaCl. With regard to temperatures, there was no significant differences found in root and total length of poppy seedlings, but the differences were very significant (p<0.01) for stem length. The longest poppy seedlings were measured at 20°C and 0 mM NaCl (4.9 cm), while at 10°C and at 0 or 50 mM NaCl, seedlings were less than 0.1 cm. Seeds were not germinating at all on 10°C on both, 100 and 150 mM NaCl. Generally, salinity reduced germination energy and germination rate and seedlings length. Results may indicate that seeds are mainly affected by osmotic stress and therefore it is not recommended to cultivate poppies on soils with excess salts

Specialized Plant Growth Chamber Designs to Study Complex Rhizosphere Interactions

The rhizosphere is a dynamic ecosystem shaped by complex interactions between plant roots, soil, microbial communities and other micro- and macro-fauna. Although studied for decades, critical gaps exist in the study of plant roots, the rhizosphere microbiome and the soil system surrounding roots, partly due to the challenges associated with measuring and parsing these spatiotemporal interactions in complex heterogeneous systems such as soil. To overcome the challenges associated with in situ study of rhizosphere interactions, specialized plant growth chamber systems have been developed that mimic the natural growth environment. This review discusses the currently available lab-based systems ranging from widely known rhizotrons to other emerging devices designed to allow continuous monitoring and non-destructive sampling of the rhizosphere ecosystems in real-time throughout the developmental stages of a plant. We categorize them based on the major rhizosphere processes it addresses and identify their unique challenges as well as advantages. We find that while some design elements are shared among different systems (e.g., size exclusion membranes), most of the systems are bespoke and speaks to the intricacies and specialization involved in unraveling the details of rhizosphere processes. We also discuss what we describe as the next generation of growth chamber employing the latest technology as well as the current barriers they face. We conclude with a perspective on the current knowledge gaps in the rhizosphere which can be filled by innovative chamber designs.

Validation of Screening Technique for Cotton Bacterial Blight Resistance under Controlled Condition

Seven different methods of artificial inoculation such as 1. Carborundum injury, 2. Pin prick injury 3. Sand paper injury, 4. Syringe inoculation on lower surface of leaf without needle, 5. Syringe inoculation of veins on lower surface of leaf with needle, 6. Tooth picks inoculation on collar region and 7. Pressurized spray inoculation were evaluated to find out the efficient and precise screening method for cotton bacterial blight caused by Xanthomonas citri pv. malvacearum under controlled conditions (plant growth chamber). Inoculated seedlings were incubated at 28°C, 90% RH and 3000 LUX light intensity during day time and 22°C, 90% RH and absence of light during night time for symptom development. Among them, pin prick injury recorded maximum PDI (64.25) in 20-24 days post inoculation followed by sand paper injury (56.50 PDI) in 23-27 days post inoculation on 20 day old LRA 5166 cotton seedlings compared to other methods. Both these methods developed all types of symptoms. Initial symptom of water soaked lesion was appeared in 7-8 days post inoculation in pin prick injury while it was 9-10 days in sand paper injury.

High frequency measurements reveal distinct sources of shoot methane emissions.

<p>Plant shoots can emit methane (CH<sub>4</sub>) from multiple source processes (microbial methanogenesis in soils and core wood, aerobic CH<sub>4</sub> production in foliage). We constructed a chamber system to isolate these processes and study how leaf level CH<sub>4</sub> emissions respond to environmental factors like dark-light-cycles, temperature, drought, or CO<sub>2</sub> concentrations. Tree samplings are located in a FITOCLIMA D 1200 plant growth chamber for PAR, temperature and humidity control and equipped with a measurement chamber to quantify CH<sub>4</sub> exchange in a closed loop setup with a Picarro G2301 CH<sub>4</sub> analyser. The system was further customized to control temperature, CO<sub>2</sub>, and humidity in the measurement chamber. The system allows the detection of CH<sub>4</sub> flux rates of on the order of 1 nmol CH<sub>4</sub> h<sup>-1</sup> and can conduct high frequency (< 15 min) measurements of CH<sub>4</sub> emissions rates from small shoots (<5g foliage biomass). Initial measurements were conducted with Scots pine and birch saplings. In addition, we measured conducted manual methane flux measurements on shoots of Scots pine saplings in two 24-hour campaigns.</p><p>These experiments demonstrated that the shoots of different tree species emit CH<sub>4</sub> from distinct sources. Scots pine shoots emitted CH<sub>4</sub> produced within the shoot, likely through aerobic CH<sub>4</sub> production, which showed a strong diurnal cycles that follows irradiation and photosynthesis rates. Shoot from some birch species, in contrast, showed emissions of soil-borne CH<sub>4</sub> that remained constant throughout day and nighttime. We expect that future experiment with this unique setup will allow to further disentangle shoot CH<sub>4</sub> emissions and characterize their response to environmental conditions including light, temperature, and relative humidity.</p>

Selecting for Chlamydomonas reinhardtii fitness in a liquid algal growth system compatible with the International Space Station Veggie plant growth chamber

A biological life support system for spaceflight would capture carbon dioxide waste produced by living and working in space to generate useful organic compounds. Photosynthesis is the primary mechanism to fix carbon into organic molecules. Microalgae are highly efficient at converting light, water, and carbon dioxide into biomass, particularly under limiting, artificial light conditions that are a necessity in space photosynthetic production. Although there is great promise in developing algae for chemical or food production in space, most spaceflight algae growth studies have been conducted on solid agar-media to avoid handling liquids in microgravity. Here we report that breathable plastic tissue culture bags can support robust growth of Chlamydomonas reinhardtii in the Veggie plant growth chamber, which is used on the International Space Station to grow terrestrial plants. Live cultures can be stored for at least one month in the bags at room temperature. The gene set required for growth in these photobioreactors was tested through a short-wave ultraviolet light (UVC) mutagenesis and selection experiment with wild-type (CC-5082) and cw15 mutant (CC-1883) strains. Genome sequencing identified UVC-induced mutations, which were enriched for transversions and nonsynonymous mutations relative to natural variants among laboratory strains. Genes with mutations indicating positive selection were enriched for information processing genes related to DNA repair, RNA processing, translation, cytoskeletal motors, kinases, and ABC transporters. These data suggest modification of signal transduction and metabolite transport may be needed to improve growth rates in this spaceflight production system.