Plant Growth Chamber Research Articles

Characterization for drought resistance at early stages of wheat genotypes based on survival, coleoptile length, and seedling vigor

In order to develop genotypes having a stable higher yield, it is necessary to characterize genetic resources based on drought adaptation, determine the suitable genotypes, and use them in breeding programs. This study was carried out in greenhouses, plant growth chambers, and research farms of the Faculty of Agriculture at Ataturk University. A total of 64 certified and local bread wheat genotypes were used to test survival after drought, coleoptile length, and seedling vigor. There were significant differences with respect to the selection parameters in this study. Seedling survival ranged from 18.5% to 51.1% and coleoptile lengths were 39-74 mm. Leaf width and specific leaf area were 3.27-4.71 mm and 164.4-204.2 cm 2 /g, respectively. Genotypes Lancer, Kirac 66, Gerek 79, Mizrak, Harmankaya 99, Alparslan, Dagdas 94, and Dogu 88 had stable high seedling survival rates and were tolerant to early drought with respect to seedling survival after drought. Local genotypes and old cultivars had higher coleoptile length compared to modern cultivars. Genotypes Ak Bugday, Tir, Lancer, Sert Bugday, and Conkesme, having long coleoptiles, could be used as genitors for the breeding of new genotypes with short plant height and longer coleoptile. Genotypes Kirac 66 and Mufitbey, ranked best in terms of first leaf width and specific leaf area, could adapt themselves to places where early drought is observed and could be used as parents in breeding programs.

Germination of rye brome (Bromus secalinus L.) seeds under simulated drought and different thermal conditions

The aim of the present study was to compare the germination of rye brome (<em>Bromus secalinus </em>L.) seeds and the initial growth of seedlings under simulated drought and different thermal conditions. The study included two experiments carried out under laboratory conditions in the spring of 2012. The first experiment involved an evaluation of the speed of germination as well as of the biometric characters and weight of seedlings in polyethylene glycol solutions (PEG 8000) in which the water potential was: -0.2; -0.4; -0.65; -0.9 MPa, and in distilled water as the control treatment. The experiment was conducted at the following temperatures: 25/22oC and 18/14oC day/night, at a relative air humidity of 90%. The other experiment, in which lessive soil was used as a germination substrate, was carried out in a plant growth chamber at two levels of air humidity (55–65% and 85–95%) and temperature (22/10oC and 16/5oC). The soil moisture content was determined by the gravimetric method and the water potential corresponding to it was as follows: -0.02, -0.07, -0.16, -0.49, -1.55 MPa. The germination capacity and emergence of <em>Bromus secalinus </em>as well as the weight of sprouts produced were significantly dependent on the water potential of the polyethylene glycol solution and on the soil water potential. The emergence of <em>Bromus secalinus </em>was completely inhibited by reducing the soil water potential below -0.16 MPa (the point of strong growth inhibition). The emergence and biometric characters of rye bro- me seedlings were significantly dependent on temperature and air humidity.

Wpływ miedzi na rozkład acetochloru w glebie

The aim of the studies was to determine the influence of copper on acetochlor degradation in soil. The experiment was carried out in laboratory conditions (plant growth chamber). Acetochlor was applied to two different soils (similar textures, pH, organic carbon content and contrasting copper content: soil contaminated by copper and soil with low copper concentration). Soil samples were taken for analyses 1 hour (initial concentration) and 2, 4, 8, 16, 32, 64 and 96 days after treatment. Acetochlor residue was analysed using GC/ECD (gas chromatography with electron capture detector). Good linearity was found between logarithmic concentration of acetochlor residues and time. The differences in copper content influenced the acetochlor decay in soil. Values of DT50 obtained in the experiment varied from 9 to 22 days. A high concentration of copper in soil slowed down of acetochlor degradation (the DT50 value was higher – 22 days). Celem pracy było określenie wpływu miedzi na rozkład acetochloru w glebie. Doświadczenia prowadzono w warunkach kontrolowanych (komora klimatyczna). Acetochlor aplikowano na dwie gleby o zbliżonym składzie granulometrycznym, pH i zawartości węgla organicznego, a o zróżnicowanej zawartości miedzi: gleba skażona miedzią i gleba o niskiej zawartości miedzi. Próbki gleby do analiz pobierano 1 godzinę po opryskiwaniu (stężenie początkowe), a następne po 2, 4, 8, 16, 32, 64 i 96 dniach po aplikacji herbicydu. Pozostałości acetochloru oznaczano metodą chromatografii gazowej z detektorem wychwytu elektronów (GC/ECD – gas chromatography with electron capture detector). Wyznaczone krzywe rozkładu opisano matematycznie. Najlepsze dopasowanie danych eksperymentalnych do modelu uzyskano stosując kinetyczne równanie reakcji pierwszego rzędu. Czas połowicznego rozkładu DT50 acetochloru wyniósł 9–22 dni. Zawartość miedzi w glebie miała znaczący wpływ na szybkość rozkładu i wartość wskaźnika DT50. Wolniejszy rozkład acetochloru, a tym samym wyższą wartość DT50 (22 dni), stwierdzono w glebie zanieczyszczonej miedzią.

Temperature and Saline Stress on Seedlings of Swietenia macrophylla: A Comparative Study

Physical responses of plants to change in climatic factors like temperature, precipitation and abiotic factors like salinity intrusion may lead positive or negative effects. Some factor may promulgate growth while other may stunts their vigour. Present study seeks growth of a plantation species at its early stage of life towards elevated temperature and saline water stresses. Growth records of Swietenia macrophylla seedlings were enumerated by measuring height, collar diameter and leaf number development of the replicates growing at an environment-controlled plant growth chamber. One experimented with merely elevated temperature while other tries to find results of combined effect of elevated temperature (30, 32 and 34 degrees C) and saline (0.5, 1.5 and 2.5 g L(-1) NaCl) to said species seedlings. Seedling replicates showed diverse response to elevated temperature and saline irrigation at height, collar diameter and leaf number development. Results depict that elevated temperature alone might be positive for S. macrophylla seedlings, rather most favourable for its growth in height, however, collar diameter and leaf number may remain unaffected. Saline treatment along with higher temperature stresses may lead seedlings toward stunted or very low growth. As saline intensity increases, species growth tends to decrease proportionally. Elevated temperature aided with higher salinity may direct further under development of S. macrophylla seedlings which is distressing to plantation establishment of this species in sites which are vulnerable to salinity intrusion due to climate change. However, S. macrophylla may be a promising plantation species in drier part of the globe in near future.

Optimization of somatic embryogenesis protocol in Lycopersicon esculentum L. using plant growth regulators and seaweed extracts

In the present study a simple and efficient somatic embryogenesis system was developed from leaf explants of Lycopersicon esculentum L. The protocol has been developed by using plant growth regulators and seaweed extracts a natural biostimulant. The leaf sections were initially cultured on to leaf embryogenic callus induction medium fortified with various concentration and combinations of 2,4-dichlorophenoxy acetic acid (0.2–1.0 mg L−1), picloram (0.2–1.0 mg L−1), and kinetin (0.1–0.5 mg L−1). The best responding concentration in induction of friable embryogenic callus was tested for the proliferation. The friable cultures were detached from the mother culture and inoculated in three different media supplemented with plant growth regulators, plus 0–25 % Caulerpa scalpelliformis or 0–25 % Gracilaria corticata extracts for embryo development. A twofold increase in maturation and germination of somatic embryos was observed in the media containing seaweed extracts (MSMG2 and MSMG3) than the control (MSMG1). The plantlets transferred from plant growth chamber to greenhouse conditions exhibited higher survival rate (90 %) than directly shifted plantlets.

Organ-specific remodeling of the Arabidopsis transcriptome in response to spaceflight

BackgroundSpaceflight presents a novel environment that is outside the evolutionary experience of terrestrial organisms. Full activation of the International Space Station as a science platform complete with sophisticated plant growth chambers, laboratory benches, and procedures for effective sample return, has enabled a new level of research capability and hypothesis testing in this unique environment. The opportunity to examine the strategies of environmental sensing in spaceflight, which includes the absence of unit gravity, provides a unique insight into the balance of influence among abiotic cues directing plant growth and development: including gravity, light, and touch. The data presented here correlate morphological and transcriptome data from replicated spaceflight experiments.ResultsThe transcriptome of Arabidopsis thaliana demonstrated organ-specific changes in response to spaceflight, with 480 genes showing significant changes in expression in spaceflight plants compared with ground controls by at least 1.9-fold, and 58 by more than 7-fold. Leaves, hypocotyls, and roots each displayed unique patterns of response, yet many gene functions within the responses are related. Particularly represented across the dataset were genes associated with cell architecture and growth hormone signaling; processes that would not be anticipated to be altered in microgravity yet may correlate with morphological changes observed in spaceflight plants. As examples, differential expression of genes involved with touch, cell wall remodeling, root hairs, and cell expansion may correlate with spaceflight-associated root skewing, while differential expression of auxin-related and other gravity-signaling genes seemingly correlates with the microgravity of spaceflight. Although functionally related genes were differentially represented in leaves, hypocotyls, and roots, the expression of individual genes varied substantially across organ types, indicating that there is no single response to spaceflight. Rather, each organ employed its own response tactics within a shared strategy, largely involving cell wall architecture.ConclusionsSpaceflight appears to initiate cellular remodeling throughout the plant, yet specific strategies of the response are distinct among specific organs of the plant. Further, these data illustrate that in the absence of gravity plants rely on other environmental cues to initiate the morphological responses essential to successful growth and development, and that the basis for that engagement lies in the differential expression of genes in an organ-specific manner that maximizes the utilization of these signals – such as the up-regulation of genes associated with light-sensing in roots.

Multispectral Plant Health Imaging System for Space Biology and Hypobaric Plant Growth Studies

Ensuring high plant yields is critical for the application of higher plants to space- based biological life support systems. An imager capable of monitoring several fluorescent biological markers in real-time would provide a robust health monitoring system and allow growers to minimize environmental stressors. This article reports the results of the design and development of a multispectral plant health imager prototype, employed in a low- pressure plant growth chamber as a test of its functionality in spaceflight systems. Images were collected every four hours with a monochromatic camera and a commercial liquid crystal tunable filter. This arrangement permitted the monitoring of emission from introduced green fluorescent proteins as well as chlorophyll fluorescence. Data were saved locally and accessed in real-time from the exterior of the chamber.

Ascending migration of endophytic Bacillus thuringiensis and assessment of benefits to different legumes of N.W. Himalayas

Out of twenty seven Gram positive and spore forming Bacilli, four Bacillus thuringiensis (Bt) were obtained from root nodules of six legumes. Three bipyramidal and one spherical crystal producing B. thuringiensis were isolated from root nodules of ricebean, lentil, gahat (Horsegram) and soybean plant. Double Intrinsic Antibiotic Resistance (IAR) markers were developed to detect/monitor the presence of B. thuringiensis in the natural environment. B. thuringiensis isolates were examined for their ability to enhance plant growth and ascending migration (from roots to aerial plant part) in four legumes in plant growth chamber at 28 °C. Seed bacterization with B. thuringiensis isolates positively influenced the percent germination and enhanced the plant growth of ricebean, soybean, gahat, and lentil seedlings. All B. thuringiensis isolates were recovered from rhizosphere, root endophytic region, stem lower, upper part and leaf after 45 days after sowing (DAS). Isolate VRB1 was able to colonized rhizosphere and endophytic regions (root, stem and leaf) of gahat, soybean and ricebean after 45DAS. Similarly, isolate VL4C and VLS72.1 were able to colonize rhizosphere and endophytic regions (root, stem and leaf) of lentil and soybean. While, isolate VLG15 was able to colonized rhizosphere and endophytic regions (root, stem and leaf) of lentil, soybean and gahat. Therefore, this study suggests that this approach may be utilized for the development of insect resistant crop strategy in sustainable agriculture.

Preparation of Modified Kaolin and its Properties of Water Retention

Kaolin was modified by propionamide in the present study. XRD analysis with X-ray diffractometer of Rigaku Corporation, infrared analysis with a Nicolet MagnaIR750 Fourier transform infrared (FTIR) spectroscope and the analysis of the TG and DTA curve with Composite Thermal Ana-lyzer were carried out. A Plant Growth Chamber was used to study the water-retaining property of modified kaolin. The results demonstrated that the microstructure of modified kaolin was flaky. Using the modified kaolin in arid regions the sub-surface moisture of soil can be maintained effectively, and the seedling survival rate increases obviously.

Characterizing parameters of Jatropha curcas cell cultures for microgravity studies

Jatropha (Jatropha curcas) is a tropical perennial species identified as a potential biofuel crop. The oil is of excellent quality and it has been successfully tested as biodiesel and in jet fuel mixes. However, studies on breeding and genetic improvement of jatropha are limited. Space offers a unique environment for experiments aiming at the assessment of mutations and differential gene expression of crops and in vitro cultures of plants are convenient for studies of genetic variation as affected by microgravity. However, before microgravity studies can be successfully performed, pre-flight experiments are necessary to characterize plant material and validate flight hardware environmental conditions. Such preliminary studies set the ground for subsequent spaceflight experiments. The objectives of this study were to compare the in vitro growth of cultures from three explant sources (cotyledon, leaf, and stem sections) of three jatropha accessions (Brazil, India, and Tanzania) outside and inside the petriGAP, a modified group activation pack (GAP) flight hardware to fit petri dishes. In vitro jatropha cell cultures were established in petri dishes containing a modified MS medium and maintained in a plant growth chamber at 25±2°C in the dark. Parameters evaluated were surface area of the explant tissue (A), fresh weight (FW), and dry weight (DW) for a period of 12weeks. Growth was observed for cultures from all accessions at week 12, including subsequent plantlet regeneration. For all accessions differences in A, FW and DW were observed for inside vs. outside the PetriGAPs. Growth parameters were affected by accession (genotype), explant type, and environment. The type of explant influenced the type of cell growth and subsequent plantlet regeneration capacity. However, overall cell growth showed no abnormalities. The present study demonstrated that jatropha in vitro cell cultures are suitable for growth inside PetriGAPs for a period of 12weeks. The parameters evaluated in this study provide the basic ground work and pre-flight assessment needed to justify a model for microgravity studies with jatropha in vitro cell cultures. Future studies should focus on results of experiments performed with jatropha in vitro cultures in microgravity.

Physiological Traits and Metabolites of Cacao Seedlings Influenced by Potassium in Growth Medium

Cacao (Theobroma cacao L.) is of significant economic importance in several tropical countries but its yield potentials are low mainly because of poor soil fertility especially low levels of potassium (K). Cacao has a high demand for K to maintain healthy growth and production. Knowledge of K use in cacao will help the development of suitable crop management practices and will aid breeding varieties adapted to environments with a limited soil K supply. Using a plant growth chamber, we investigated the growth and physiological traits among three cacao varieties at three levels of growth medium K (52, 156, and 469 mg·plant-1). Significant K effects were observed on growth traits including stem diameter, root length, chlorophyll b, and the ratio of chlorophyll a/b. Significant K effect was also found on carbohydrate metabolites, such as fructose, glucose, myo-inositol, raffinose and starch. However, no K effect was observed in other growth and physiological indicators, including biomass of seedling and net photosynthetic rate. There were significant genotype differences on seedling growth indicators, including stem diameter, stem height, total biomass, leaf biomass, leaf area, root length, chlorophyll a + b and carotenoids. Genotype difference was also found on all measured carbohydrate and starch metabolites, except maltose and raffinose. Results of this study indicate that although K plays a critical role in cacao tree growth and productivity, cacao may be less sensitive to K deficiency during the seedling stage. The present results improved our understanding about K and plants interaction in cacao seedlings, which is useful for crop management and germplasm utilization.

2C-methyl- d- erythritol 2,4-cyclodiphosphate synthase from Stevia rebaudiana Bertoni is a functional gene

Stevia [Stevia rebaudiana (Bertoni)] is a perennial herb which accumulates sweet diterpenoid steviol glycosides (SGs) in its leaf tissue. SGs are synthesized by 2C-methyl-D-erythritol 4-phosphate (MEP) pathway. Of the various enzymes of the MEP pathway, 2C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (MDS) (encoded by MDS) catalyzes the cyclization of 4-(cytidine 5' diphospho)-2C-methyl-D-erythritol 2-phosphate into 2C-methyl-D-erythritol 2,4-cyclodiphosphate. Complementation of the MDS knockout mutant strain of Escherichia coli, EB370 with putative MDS of stevia (SrMDS) rescued the lethal mutant, suggesting SrMDS to be a functional gene. Experiments conducted in plant growth chamber and in the field suggested SrMDS to be a light regulated gene. Indole 3-acetic acid (IAA; 50, 100 μM) down-regulated the expression of SrMDS at 4 h of the treatment, whereas, abscisic acid did not modulate its expression. A high expression of SrMDS was observed during the light hours of the day as compared to the dark hours. The present work established functionality of SrMDS and showed the role of light and IAA in regulating expression of SrMDS.

A model development approach to ensure identifiability of a simple mass balance model for photosynthesis and respiration in a plant growth chamber

A model development approach, which aims to build sufficiently simple models so as to ensure parameter identifiability, is presented and used to develop a dynamic mass balance model of photosynthesis and respiration reactions. The model was developed for the control of a highly automated plant growth chamber within the context of the MELiSSA project, a European Space Agency program which aims to develop technology for a future regenerative life support system. Simple, identifiable models are required for this application and are also valuable for other prediction and control applications, which could include the operation of greenhouses or other controlled environment agricultural systems in the future. Experiments were conducted on lettuce (Lactuca sativa cv. Lively) and red beet (Beta vulgaris cv. Detroit Medium Red) in sealed environment plant growth chambers. Environmental variables (including CO2 uptake data) were recorded throughout growth, while biomass and leaf area measurements were taken before transfer to the chamber and at harvest. The model development approach was iterative, with assessments of model reliability throughout. Major metabolic reactions with respect to plant growth were first selected and corresponding mass balance equations were written, taking structural identifiability into account. The kinetic model was selected, from several potential rate laws, based on an analysis of the fit of the model (on identification and independent validation datasets) and the reliability of the parameter estimates (practical identifiability). The application of this systematic model development approach yielded a very simple model of plant growth in which all parameters were identifiable based on the available experimental data (a unique value could be identified for each). The approach could be applied to many other crop modelling problems to obtain simple, identifiable and reliable models.

The effect of atmospheric CO2 concentration on carbon isotope fractionation in C3 land plants

Because atmospheric carbon dioxide is the ultimate source of all land-plant carbon, workers have suggested that pCO2 level may exert control over the amount of 13C incorporated into plant tissues. However, experiments growing plants under elevated pCO2 in both chamber and field settings, as well as meta-analyses of ecological and agricultural data, have yielded a wide range of estimates for the effect of pCO2 on the net isotopic discrimination (Δδ13Cp) between plant tissue (δ13Cp) and atmospheric CO2 (δ13CCO2). Because plant stomata respond sensitively to plant water status and simultaneously alter the concentration of pCO2 inside the plant (ci) relative to outside the plant (ca), any experiment that lacks environmental control over water availability across treatments could result in additional isotopic variation sufficient to mask or cancel the direct influence of pCO2 on Δδ13Cp. We present new data from plant growth chambers featuring enhanced dynamic stabilization of moisture availability and relative humidity, in addition to providing constant light, nutrient, δ13CCO2, and pCO2 level for up to four weeks of plant growth. Within these chambers, we grew a total of 191 C3 plants (128 Raphanus sativus plants and 63 Arabidopsis thaliana) across fifteen levels of pCO2 ranging from 370 to 4200ppm. Three types of plant tissue were harvested and analyzed for carbon isotope value: above-ground tissues, below-ground tissues, and leaf-extracted nC31-alkanes. We observed strong hyperbolic correlations (R≥0.94) between the pCO2 level and Δδ13Cp for each type of plant tissue analyzed; furthermore the linear relationships previously suggested by experiments across small (10–350ppm) changes in pCO2 (e.g., 300–310ppm or 350–700ppm) closely agree with the amount of fractionation per ppm increase in pCO2 calculated from our hyperbolic relationship. In this way, our work is consistent with, and provides a unifying relationship for, previous work on carbon isotopes in C3 plants at elevated pCO2. The values for Δδ13Cp we determined in our ambient pCO2 chambers are consistent with the Δδ13Cp values measured in large modern datasets of plants growing within the Earth’s wettest environments, suggesting that it may be possible to reconstruct changes in paleo-pCO2 level from plants that grew in consistently wet environments, if δ13CCO2 value and initial pCO2 level can be independently quantified. Several implications arise for the reconstruction of water availability and water-use efficiency in both ancient and recent plant Δδ13Cp values across periods of changing pCO2 level. For example, the change in Δδ13Cp implied by our relationship for the rise in pCO2 concentration observed since 1980 is of the same magnitude (= ∼0.7‰) as the isotopic correction for changes in δ13CCO2 required by the input of 13C-depleted carbon to the atmosphere. For these reasons, only the portion of the terrestrial isotopic excursion that persists after accounting for changes in pCO2 concentration should be used for the interpretation of a change in paleo-environmental conditions.

Carob trees (Ceratonia siliqua L.) regenerated in vitro can acclimatize successfully to match the field performance of seed-derived plants

The use of in vitro regenerated plants in forestry and orchard depends ultimately on the development of efficient transplantation protocols, ensuring high survival rates and successful establishment under field conditions. We tested the performance of micropropagated carob trees (Ceratonia siliqua L.) throughout the acclimatization process in terms of survival, growth and physiological traits, including field comparisons with seed-derived and mother plants. The field trial was 100 % successful, i.e. we found no major differences between micropropagated, seed-derived and mother plants in terms of growth rate, height, number of leaves, photosynthetic efficiency, chlorophyll fluorescence, chlorophyll content and soluble protein content, although these parameters changed significantly during acclimatization. Stomatal conductance (g s) was reduced by fourfold when plants were transferred from in vitro culture to the growth chamber, thus preventing uncontrolled wilting. The photosynthetic rate (P N) was relatively low in vitro, in the growth chamber and the greenhouse, but increased to match seed-derived and mother plants in the field. The chlorophyll a/b ratio in leaves from in vitro and growth chamber plants was typical of shade plants (2.1) but became more characteristic of sun plants in the subsequent acclimatization stages (3.1–3.5). The maximum efficiency of photosystem II (F v/F m) remained mostly constant at ~0.80 throughout acclimatization, as is typical for healthy, non-stressed plants. We conclude that our micropropagation and acclimatization protocols provide a suitable alternative to traditional mass propagation techniques for the carob tree.

NEXT-GENERATION, ENERGY-EFFICIENT, UNIFORM SUPPLEMENTAL LIGHTING FOR CLOSED-SYSTEM PLANT PRODUCTION

Two relatively new, energy-efficient lamp types and light delivery systems for plant growth chambers were compared in matched 2.44 x 3.66 m walk-in plant growth chambers. The chambers were lit either by ninety-six 1.22 m long 54 W cool white HO T5 fluorescents arranged to cover the chamber ceiling, or by fourteen 315watt ceramic metal halide HID lamps arranged in two rows. The fluorescents were contained in twelve 0.61 x 1.22 m luminaires (Sunlight Supply Systems, Model 960202), each containing a reflector and eight tubes. The HID lamps were housed in custom-designed luminaires (Cycloptics All-Bright 315W) with reflectors mounted above the ceiling of the chamber, opening into the chamber. Light intensities were measured at the centers of ninety-six (8 x 12) uniformly sized grid squares in five planes below the ceiling, from 0.76 to 1.98 m down, with the walls and floor of the chamber below the plane of measurement made non-reflective by covering it with black material, and keeping the chamber empty and the door closed. Wattage required by the lamps and ballasts showed the HID system provided 40% to 60% more light per watt than the T5 system, with light distributed more uniformly in the three lowest planes. A T12 fluorescent system (forty-eight 215-watt VHO cool white lamps,) with which the growth chambers were previously lamped, was also compared to the T5 fluorescent and HID systems, using measurements for single quadrants of the chambers. This was found similar to the T5 system in light distribution uniformity, but inferior to both in terms of energy efficiency. The T5 system provided nearly four times more light per watt than the T12 system, and the HID system provided five and a half to more than six times more light per watt.

Artocarpus chaplasha: Establishment and Initial Growth Performance at Elevated Temperature and Saline Stresses

Like any other natural resources, forest flora may experience the extreme threat of elevated temperature and saline water submergence at different stages of their lives i.e. from germination to maturity due to climate change effects. The overall aim of the study was to measure the effect of higher temperatures along with saline water irrigation on survival and initial growth during seedling stage of Artocarpus chapalasha. The experiment was conducted in temperature- humidity-photoperiod regulated plant growth chamber during stipulated period to measure the growth performance of randomly selected seedlings. Within three different elevated temperatures viz. <TEX>$30^{\circ}C$</TEX>, <TEX>$32^{\circ}C$</TEX> and <TEX>$34^{\circ}C$</TEX>, the seedlings were given three different saline conditions such as 0.5 g/L, 1.5 g/L and 2.5 g/L NaCl concentrations. Results found from the experiment was that, seedlings of Artocarpus chaplasha reared at different temperatures and saline water treatments showed stunted growth than reared at existing outdoor temperature (<TEX>$26.31^{\circ}C$</TEX>) irrigated with regular fresh water. Seedling growth at three different parameters such as height, collar diameter and number of leaves showed that with increasing temperature individuals respond negatively to increasing saline condition. The seedling's growth occurred at every day in height, collar diameter and leaf. However, growth rate reduced later during the observation. The combined effect of high salinity and higher elevated temperature results in seedling mortality. Therefore, Artocarpus chaplasha may not thrive at higher temperature and salinity intrusion at its early growing period in plantation and natural forest areas.

Metamitron decay in soil depending on herbicide formulation and application methodRozkład metamitronu w glebie w zależności od formulacji i sposobu aplikacji herbicydu

Summary The aim of the studies was to determine the influence of herbicide formulation and application method on metamitron decay in soil. Experiment was carried out in the laboratory conditions (plant growth chamber). Metamitron was applied in three variants as: monocomponent herbicide (A), as monocomponent herbicide in tank mixture with herbicide containing ethofumesate, desmedipham and phenmedipham (B) and as multicomponent herbicide containing four active components (listed above); (C). Concentation of metamitron was the same in all variants. Soil samples were taken for the analyses 1 hour (initial concentration) and 2, 4, 8, 16, 32 and 64 days after treatment. Metamitron residue was analysed using GC/MS. Good linearity was found between logarithmic concentration of metamitron residues and time. The formulation and application method influenced on the metamitron decay in soil. For the variant A the DT50 value amounted to 19 days. Application of metamitron as a tank mixture (variant B) slowed down the degradation of metamitron in soil – DT50 amounted to 23 days. The DT50 value of metamitron applied in variant C was the smallest and amounted to 17 days.

Moon Plants as Model System for Life Support to Enable Human Exploration

We propose to develop a plant growth chamber for the Moon. Our goal is to support germination over a 5-day period in a spacecraft on the Moon. The system will validate the ability of plants to provide fundamental life support for future human exploration. The autonomous system provides basic environmental control to grow the plants under harsh lunar conditions characterized by high radiation and partial gravity.Several innovative technologies are brought together for this lunar plant growth module; solar concentrators that allow light to get to the plants while increasing the power of solar arrays by 2-3 times, wireless communications that allow a sealed environment to communicate with the spacecraft, and a strain of plants tailored to survive lunar night.This integration of new technology to support plant growth ultimately contributes to human exploration.

Effect of cold-water irrigation on bacterial wilt pathogen of tomato

Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating bacterial diseases of plants worldwide. Management of bacterial wilt in tomato and other crops has been difficult, and so novel but easily implemented control methods are being sought. To evaluate the effect of cold-water irrigation on bacterial wilt of tomato, four treatments were used in which CF (chemically fertilized) soil and CF + FYM (chemical fertilizer + farmyard manure [FYM]) soil were inoculated with a bacterial suspension (R. solanacearum strain YU1Rif43) at 106 colony forming units (CFU) g−1 soil. Tomato seedlings were grown in Agri-pots in a plant growth chamber. The soil was irrigated with water that was kept at the same temperature in each treatment: 4, 10, 20, or 30°C. Incidence and severity of wilt, counting of the colonies of the culturable population of pathogen, and dry-mass and height of the plants were examined. After 45 days and in both kinds of soil, most of the plants had wilted in soil irrigated at 30°C. Wilt incidence was substantially reduced when transplanted seedlings were irrigated at lower temperatures (4–20°C). Survival of R. solanacearum was also reduced after being irrigated with water at lower temperatures, indicating that the reduced incidence of wilt was linked to reduced survival of the pathogen. Dry-mass and plant height were slightly higher under control conditions than in soils irrigated at lower temperatures. This study suggests that cold-water irrigation could significantly reduce bacterial wilt of tomato and have an adverse effect on survival of the wilt pathogen.