Total Plant Dry Weight Research Articles

Morphological traits and growth studies of some promising chickpea [<em>Cicer arietinum</em> (L.)] genotypes

The morphological traits and growth studies of crop varieties are important feature that may help to better understand their inherent capacity or energy to stand as well as to know their pattern of growth. With this target, a field experiment was conducted in order to study the morphological traits and growth patterns of nine promising chickpea genotypes namely, AGBL-184, IPC-2010-94, IPC-2011-70, ICCV-13107, RSG-888, 24001-4-1, 24004-3-1, 24034-4-1 and 24017-1-1. Following randomized complete block design with four replications, the observations on several growth parameters were taken at fortnight intervals, starting from 15 DAS to 60 DAS. The parameters taken were plant height, leaf number, leaf area, leaf dry weight, shoot dry weight and total plant dry weight. The pattern of growth based on the morphological traits of the genotypes was different in respect of their pattern of stem elongation, leaf area expansion, dry matter accumulation in leaf, shoot as well as whole plant. However, some common points were also noticed. The result revealed that, major proportion of stem elongation occurred within 30 DAS, whereas, leaf expansion in early growth stage was nominal but made a huge jump around flowering stage for all the genotypes. A huge enhancement in dry matter production in leaf, shoot and total plant was observed at post flowering stage. Correlation analysis showed that the parameters leaf area, leaf dry weight, shoot dry weight as well as total plant dry weight were found to be strongly associated with the seed yield. The highest yielder was genotype AGBL-184 that also maintained highest leaf and total plant dry weight irrespective of the growth stages. In terms of leaf area and shoot dry weight also, AGBL-184 was among the top-ranking genotypes.

Genetic variation for leaf carbon isotope discrimination and its association with transpiration efficiency in canola (Brassica napus).

Drought is a major constraint to canola production around the world. There is potential for improving crop performance in dry environments by selecting for transpiration efficiency (TE). In this work we investigated TE by studying its genetic association with carbon isotope discrimination (Δ) and other traits, e.g. specific leaf weight (SLW) and leaf chlorophyll content (SPAD). Among the 106 canola genotypes - including open-pollinated, hybrid, inbred types and cytoplasmic variants - tested in the field and glasshouse there was significant genotypic variation for TE, Δ, plant total dry weight, SLW and SPAD. Strong negative correlations were observed between TE and Δ (-0.52 to -0.76). Negative correlations between Δ and SLW or SPAD (-0.43 to -0.78) and smaller but significant positive correlations between TE and SLW or SPAD (0.23 to 0.30) suggested that photosynthetic capacity was, in part, underpinning the variation in TE. A cytoplasmic contribution to genetic variation in TE or Δ in canola was also observed with Triazine tolerant types having low TE and high Δ. This study showed that Δ has great potential for selecting canola germplasm with improved TE.

The Effects of Vermicompost and Phosphorus on the Development of Soybean Plant

Aims: Vermicompost (worm manure), which has gained importance in the last quarter of the century among innovative agricultural practices, has positive effects on both plant development and soil structure. The shortage of organic matter in soil reduces the productivity of agricultural production and hampers its continuity. Vermicompost products confer plant nutrient elements, various hormones, enzymes, humic substances and especially organic matter to the soil. This study aimed to study the effects of vermicompost application and phosphorus fertilizer rates on soybean in limy soil conditions.
 Study Design: The affect of vermicompost applications was evaluated with four doses of vermicompost (Control, 1.5, 3, and % 6) in three doses of phosporus applications. So, 0, 50 ppm and 100 ppm phosporus blocks had all four doses of vermicompost. Optimum level (100 ppm N and 100 ppm K) of N and K fertilisers were applied to all plants tested. Total plant biomass, leaf wet and dry weights, bean wights, plant height and nitrogen compositions of leaf and bean were measured.
 Results: The results were detected significant at % 1 on all parameters. As control plants’ leaf + scape wet and dry weights were measured 3.29 and 1.23 g respectively, they were measured 8.6 and 5.22 g at plants used vermicompost and phosphorus together. With vermicompost and phosphorus aplications, the phosphorus and nitrogen uptakes increased too. While control plants’ leaves have % 0.38 phosphorus content, it was measured % 0.84 at plant aplicated vermicompost and phosphorus.
 Coclusion: As a result, we observed increased P uptake levels with increased doses of vermicompost application in limysoils.

Imbalanced Ca/Mg and Ni excess effects on the growth, nutrient uptake, photosynthesis and antioxidant response of Punica granatum (cv. Granada) plants

Imbalanced Ca/Mg and excess Ni (due to serpentine stress) are limiting factors for plant productivity. The purpose of this study was to investigate if growth, nutrient uptake, PSII activity, photosynthesis and antioxidant activity of pomegranate (Punica granatum L., cv. Granada) plants were affected by serpentine stress. Pomegranate plants were grown in soil substrates from parent material marl (control), serpentine and serpentinized peridotite. Plant height, leaf, stem, root and total plant dry weight, as well as foliar N, P, K, Ca, Zn, Cu, chlorophyll content, fluorescence parameters, photosynthetic rate, and internal water use efficiency (WUEi) were significantly lower for the plants grown in the serpentinized peridotite soil. In contrast, higher ferric reducing antioxidant power (FRAP), total phenolics and total flavonoid content (TFC) levels were found in the serpentinized peridotite soil. The insignificant differences between the marl and serpentine soils in plant growth, PSII activity, photosynthesis and nutrient uptake indicated that P. granatum could tolerate a mild (not with extremely high Ni) serpentine stress. However, P. granatum could not tolerate stress showing excess Mg and imbalanced Ca/Mg, as found for the serpentinized soil of our study.

Growth response of cacao (Theobroma cacao L.) plant as affected by bamboo biochar and arbuscular mycorrhizal fungi in sterilized and unsterilized soil

Abstract Biochar and arbuscular mycorrhizal fungi (AMF) are found to improve crop productivity affecting the nutrient availability in the soil and favoring build-up of beneficial microbes. The effects of AMF and bamboo biochar (BB) on the growth of cacao, estimated number of mycorrhizal spores, and soil chemical properties were investigated. Cacao seedlings were grown in unsterilized and oven-sterilized acidic soil. After 15 months, AMF generally increased most growth traits of cacao plant over the control. Bamboo biochar at 15%, gave the best plant growth regardless of soil sterilization. When biochar was added to AMF, 15% consistently provided the heaviest total plant dry weight, especially in unsterilized soil. Likewise, all treatments improved the height and stem diameter increments of those grown in unsterilized soil. Percentage of mycorrhizal root colonization was higher in mycorrhizal (+AMF) plant and addition of biochar proliferated AMF spores in the rhizosphere. Biochar showed positive effect in enhancing the soil chemical properties. The results imply that biochar and AMF can improve the overall growth and can positively increase the yield of cacao plants, which will provide impact in improving cacao production in acidic soils in the Philippines.

Growth and Yield Response of Maize (Zea mays L.) on Acid Soil to Different Rates of Humic Acid and NPK Fertilizer

The main constraint in the extensification of maize on the dry land of acid soil is the low availability of P in soil. This study aimed to determine the effect and the optimal dose of humic acid on the growth and yield of maize on acid soil. This research was conducted from February to May 2017 at Tri Dharma Field Laboratory, Faculty of Agriculture, Gadjah Mada University. Acid soil with low P availability used was from sub-district Cigudeg and Jasinga, West Java. The research was arranged in Randomized Complete Block Design (RCBD) with 2 factors. The first factor was maize cultivar, namely Bisi 2 and Pioneer 35. The second factor was the rate of humic acid and NPK fertilizer, consisting of 0 kg.ha-1 (without) NPK and 0% (without) humic acid, NPK + 0% (without) humic acid, NPK + 5% humic acid, NPK + 10% humic acid, and NPK + 15% humic acid. NPK fertilizer applied was NPK 16:16:16 at a dose of 350 kg.ha-1. The results showed that humic acid application on acid soil increased C-humic content in the soil, soil P availability, total dry weight of the plant, and kernel dry weight at harvest (15 weeks after planting). The increase in soil P availability did not improve the plant growth but increased the accumulation of plant biomass. The application of humic acid at 15% (52.5 kg.ha-1) combined with NPK fertilizer on acid soil significantly increased total dry weight of plant and kernel dry weight up to 13.14% and 21.81%, respectively, thus, it is recommended for maize cultivation on acid soil.

Changes in yield components, morphological, physiological and fruit quality traits in processing tomato cultivated in Italy since the 1930’s

Yield of processing tomato (Solanum lycopersicum L.) increased (∼ 50%) in Italy since the 1930’s. The aim of this work was to assess the changes in yield components associated with morphological, physiological and fruit quality traits in processing tomato cultivars cropped in Italy from the mid-1930s until nowadays, introduced by breeding in six representative cultivars. Marketable yield showed an increase of 0.6% per year of release since the 1930’s. The highest marketable yield was obtained in modern cultivars due to a higher harvest index, fruit number and the ratio between ripe fruit and total fruit in comparison with the old ones. However, no single trait drove the highest marketable yield in modern cultivars. In fact, both morphological (smaller plant height and leaf area index) and physiological (accelerated plant senescence, higher leaf nitrogen status, and lower potential plant water and chlorophyll contents) traits contributed to increase marketable yield in modern cultivars. Moreover, total plant dry weight (shoot + fruit) of a single plant decreased, whereas its total fruit fresh weight and fruit dry matter content were stable and not correlated with the year of release, thus suggesting that a higher sink strength and homogeneity of fruit ripening were also involved in the highest marketable yield showed by modern cultivars. A great effort of breeders was done in the improvement of important fruit quality traits required by Italian canning industries. Fruit colour and Brix yield were positively correlated with the year of release, while viscosity and total carotenoids were negatively correlated with the year of release. However, no improvement was achieved for important traits such as soluble solids content, fruit dry weight and total fruit yield, which instead should be considered in the future breeding programmes, to improve both yield and quality of processing tomato.

Silicon attenuates sodium toxicity by improving nutritional efficiency in sorghum and sunflower plants

Salt stress is known to negatively affect the fundamental processes in plants, reducing their growth and yield. The role of Silicon (Si) to protect the sorghum and sunflower plants against salinity stress was assessed. The objective of this study was to evaluate the effects of different forms of Si application on the uptake and use efficiency of macronutrients and micronutrients in sorghum and sunflower plants under salinity stress under greenhouse conditions. Two experiments were conducted using sorghum and sunflower under greenhouse conditions. Four Si levels were applied to plants: no Si application; foliar application of 28.6 mmol.L−1; root application of 2.0 mmol.L−1; and combined Si application with both via nutrient solution and foliar spraying. Each Si treatment was applied in the absence and presence of NaCl (100 mM). Thirty days after treatments, sodium (Na+) and Si accumulation, nutrient uptake and use efficiency, and the roots and total plant dry weight were measured. Salinity stress induced nutritional imbalance and decreased dry weight production in both plant species. Our results showed that Si application alleviated the salinity stress by decreased Na+ uptake and increased nutritional efficiency, thereby favoring the total plant dry weight in sorghum by 27% and sunflower by 41%. This occurred when Si was applied either via root or in combination via root and foliar application, respectively. Collectively, our findings indicate that Si application can attenuate the deleterious effects of salt stress and increase yield in sorghum and sunflower plants in a sustainable manner.

Growth and physiological responses of perennial ryegrass to an AMF and an Epichloë endophyte under different soil water contents

Arbuscular mycorrhizal fungi (AMF) and endophytic Epichloe are two important symbiotic microorganisms of perennial ryegrass (Lolium perenne). The present study evaluates the individual and combined effects of AMF and Epichloe on drought stress. Plant growth, phosphorus (P) uptake, chlorophyll content, net photosynthetic rate (Pn), soluble sugar concentration, malondialdehyde (MDA) concentration, and antioxidant enzyme activities were measured in a greenhouse experiment. Both AMF and Epichloe significantly increased Pn and total P content for each soil water content. In addition, the presence of AMF increased plant total dry weight, root activity, and soluble sugar concentration at each soil water content. Furthermore, catalase activity increased and MDA concentration decreased at 30% soil water content (SWC). Infection with Epichloe increased the polyphenol oxidase activity of plants for both non-AMF and AMF treatments at 30% SWC. AMF + Epichloe treatments increased plant P uptake, Pn, root activity, and soluble sugar concentration at each soil water content (SWC) (P < 0.001), and increased peroxidase (POD) activity at 30% SWC (P < 0.001). Plant-AMF-Epichloe symbiosis alleviated the damage caused by drought stress by promoting P uptake, photosynthesis, and the accumulation of osmoregulatory substances.

CONTROL OF DROUGHT STRESS IN TOMATO PLANTS USING SOME CULTURAL PRACTICES

In this study, tomato plants cv. Alisa were irrigated with three different amounts of water i.e. optimum amount which was the amount of water that added to raise soil field capacity (FC) from 70% (as re-irrigated tomato when FC drop to 70% is considered the most suitable irrigation regime) to 100% (T1), 66% (T2) and 33% (T3) of optimum water amount. Also, three different drought adaptable treatments were applied to tomato plants, i.e. drought pretreatment of seedlings (seedling priming), spraying plants with a reflecting antitranspirant (a suspension of calcium carbonate at concentration of 6%) or infected plants with arbuscular mycorrizal fungus, as well as control which was not treat with any of adaptable treatment. Decreasing amount of irrigation water applied decreased gradually plant height, fresh and dry weights of plant organs, leaflet area, No of days to the first anthesis (F50), fruit set percentage, relative water content (RWC), N, P and K and total carbohydrate contents in leaves, No of fruits/ plant, average fruit weight and early and total yields, than those of well-watered plants (T1). water deficit treatments (T2 & T3) enhanced root length, leaflet thickness, osmotic pressure (OP) in leaves, water use efficiency (WUE) and improved fruit quality i.e. increased vit. C, TSS, titratable acidity, and lycopene contents and fruit firmness in ripe fruits. In addition, water deficit treatments altered dry matter distribution in tomato plants as it enhanced dry mater partitioning to roots on the expense of above ground organs. All adaptable treatments used, often alleviated the detrimental effects of water deficit treated plants (T2&T3) as they promoted plant growth and productivity of both well watered and water stressed plants than those of untreated (control) plants. In most cases, spraying plants with the antitranspirant material gave the highest values of growth characteristics and yield and its components with well watered treatment (T1) and moderate water stress treatment (T2) but not with severe water stress treatment (T3). Using mycorrizal inoculation treatment gave the highest values of P content in leaves, and average fruit weight. Also it gave the second highest values (as average of the effect of the three water regimes) of plant growth, plant water relations and productivity characters alternately with drought pretreatment. In addition, mycorrizal treatment gave the highest total yield and highest total plant fresh and dry weights when combined with lowest water supply (T3) than those obtained by other two adaptable treatment.

Effects of Artificial Light Treatments on Growth, Mineral Composition, Physiology, and Pigment Concentration in Dieffenbachia maculata “Compacta” Plants

Specific wavebands may allow precise control of plant growth. However, light sources must be carefully evaluated before the large-scale use of supplemental light sources can be implemented. Dieffenbachia maculata “Compacta” plants were grown for 8 weeks in pots in a growth chamber under tightly controlled temperature and humidity in order to assess the effects of supplemental light. Three treatments were applied: (i) using 18-W fluorescent bulbs (T1), (ii) using the same bulbs with supplemental light emitting diodes (LEDs) (Pure Blue and Pure Red Mix-Light-Emitting Diodes (BR-LEDs)) (T2), and (iii) using high-efficiency TL5 fluorescents (T3). Plant biomass, mineral composition, and physiological and photosynthetic parameters were assessed under each light treatment. Total plant dry weight was highest in plants grown under treatments T1 and T3. Other differences were observed between different light treatments, including variation in biomass partitioning as well as N and K concentrations in roots, stems, and leaves. Further, proline and indole 3-acetic acid (IAA) levels were higher in plants grown under the T1 treatment, whereas total soluble sugars and starch were higher in plants grown under treatment T3. Plants grown under treatment T1 had the lowest chlorophyll concentrations. No differences were observed in organ water content and P concentration. T2 was not the best treatment, as expected. The model proposed a linear regression between integrated use of spectral energy (IUSE) and total dry weight (TDW), which showed a good relationship with an R2 value of 0.83. Therefore, we recommend this methodology to discern the effects of the different spectral qualities on plant biomass.

Ascophyllum nodosum extract improves phenolic compound content and antioxidant activity of medicinal and functional food plant Achillea millefolium L.

Genetic, biochemical and physiological parameters can be changed by applying seaweed extract-based products. However, there is scarce information about the influence of seaweed extract on yarrow performance (Achillea millefolium L.), which is widely used in the folk medicine. Therefore, this study aimed to evaluate the effects of Ascophyllum nodosum extract on plant development (leaf and root biomass, and leaf area), physiological indexes (leaf weight ratio, and root: leaf ratio), secondary metabolite (phenolic compounds) content and antioxidant activity of yarrow. The experiment was carried out in a completely randomized design with 4 treatments (seaweed extract concentrations 0, 3, 6 and 9 mL L-1) and 10 replications. The higher concentration of seaweed extract caused higher total dry weight of plants (from 17.8 to 19%), especially due to increases in the root biomass (up to 28.5%). Only plants that received the highest concentration of seaweed-based product presented increments in the number of leaves when compared to the control plants (18.3 %). Furthermore, the use of A. nodosum extract 9 mL L-1 provided increases in the antioxidant activity and content of phenolic compounds in leaves (up to 30.44%). In conclusion, application of A. nodosum is a potential tool strategy to improve the quality of raw material from yarrow plants, since it increased the phenolic compound content and antioxidant activity in leaves, which are the plant organs commonly used in folk medicine.

Effect of Cow Urine-Based Bioformulations on Growth and Physiological Responses in Mungbean Under Soil Moisture Stress Conditions

Experiments were conducted to evaluate the influence of cow urine-based bioformulations on the morphological, physiological growth response and expression of stress responsive genes under drought stress in mungbean [Vigna radiata (L.) Wilczek] plants. An initial in vitro evaluation and three separate pot experiments were carried out by treating mungbean with varying concentrations of bioformulations under different soil moisture conditions (well watered and water stressed). The application of bioformulations (BR and SH) led to an increase in number of nodules (22.41 in R3 stage under stress; 12.17 in R5 stage under stress recovery) and total plant dry weight (1.12 g in R3 stage under stress; 1.22 g in R5 stage under stress recovery) at different growth stages and soil moisture conditions. Least decrease or no change in photochemical efficiency of PS-II (Fv/Fm) in the bioformulations-treated plants under stress-imposed conditions indicated that bioformulations used in this experiment have potential role in mitigating soil moisture stress in crops like mungbean. The enhanced expression of genes of membrane-integrated protein like aquaporins (Nodulin 26-like Intrinsic Proteins—NIP) in the treated plants under low soil moisture conditions further accentuated the efficacy of these bioformulations to alleviate the drought stress in crops.

Maximizing Ecosystem Services in Jatropha curcas ; The Appropriate Planting Method

The study, which was a pot experiment, was carried out to evaluate the effect of depth of planting on growth and flowering of physic nut (Jatropha curcas). It was conducted at the Sinna Garden, Department of Crop Science, University of Ghana. Seeds were planted at different depths of 2 cm, 4 cm and 6 cm using completely randomized design. Data were collected on leaf number per plant, number of flowers produced per plant, plant height, girth of the stem, canopy size, number of branches per plant, total leaf area, and total plant fresh and dry weight. Growth analysis was performed and correlation among characters also analyzed. Results obtained in the studies revealed that percent emergence deceased with increased depth of planting and significant differences were observed in percent emergence among the different depths of planting. The 2 cm planting depth proved to be the most effective depth to achieve high emergence rate while the 6 cm was the least. Planting depths of 2 cm and 6 cm were the best in terms of growth parameters and flowering production. In all the analyses conducted, it was observed that planting Jatropha curcas seeds at 2 cm and 6 cm depths yielded the highest number of flowers, growth rate, and biomass production. Therefore, the study recommended that in order to ensure faster growth to maximize the benefits from Jatropha curcas in terms of ecosystem services delivery; it is highly recommended that you plant at 2cm and 6 cm.

Effect of Node Position and Number of Stem Cutting on The Growth and Yield of ‘katuk’ (Sauropus androgynus (L.) Merr.)

Katuk (Sauropus androgynus (L.) Merr.) has potential as a vagetable and medicinal plant. This study aimed to determine effect of node position and number of stem cuttings on the growth of katuk. The experiment used Completely Randomized Design with two treatments arranged in split plots. The node position of stem cuttings as the main plot consists of top stem cutting (T, top – 8 nodes under shoot tip), middle stem cutting (M, 8 – 11 nodes under shoot tip) and bottom stem cutting (B, 16-20 nodes under shoot tip). The node number of stem cuttings as a subplot consists of 2 nodes (J1), 3 nodes (J2), 4 nodes (J3), and 5 nodes (J4). Each treatment combination was replicated three times.The results revealed that the top stem cutting resulted in the highest root, total plant dry weight and leaf area, as well stem cutting with 4 nodes produced the highest total plant dry weight and leaf area.

Does planting time affect the nutritional demand and yield of potato cultivars?

ABSTRACT: Determining the level of absorption of nutrients in the potato crop at different stages of development is important because it allows identification of the time when the elements are most required by plants. The objective of this research was to evaluate the level of nutrient absorption in cultivars after different planting times. Field experiment was conducted in Guarapuava-PR. Treatments consisted of three cultivars (Agata, BRS Clara, and BRS F63 Camila) and two planting times (October and February), in randomized blocks, with three replications in the crop season 2015/16. The total macro and micronutrient content (leaves, stems, and tubers) was quantified at 15 and 45 days after plant emergence. The total dry weight of plants was verified at 45 days after emergence. At harvest, dry weight of tubers, and total and commercial yield was recorded. It was observed that BRS F63 Camila produced a higher total dry weight of plants at 45 days after emergence, and higher dry weight of tubers at harvest because of the higher accumulation of Fe, Mn, and Zn following the October planting. The BRS Clara produced higher total dry weight and higher dry weight of tubers following February planting with higher Ca and S accumulation. Depending on the developmental period and planting time, cultivars differed in nutrient accumulation and tuber dry weight production. Greater nutritional demand and higher yield occurred following the October planting.

Nitrogen Fertilization and Irrigation Frequency Affect Hydrangea Growth and Nutrient Uptake in Two Container Types

Plant growth, water use, photosynthetic performance, and nitrogen (N) uptake of ‘Merritt’s Supreme’ hydrangea (Hydrangea macrophylla) were investigated. Plants were fertilized with one of five N rates (0, 5, 10, 15, or 20 mm from NH4NO3), irrigated once or twice per day with the same total daily amount of water, and grown in either a paper biodegradable container or a traditional plastic container. Greater N rate generally increased plant growth index (PGI) in both plastic and biocontainers. Leaf and total plant dry weight (DW) increased with increasing N rate from 0 to 20 mm and stem and root DW were greatest when fertilized with 15 mm and 20 mm N. Plants fertilized with 20 mm N had the greatest leaf area and chlorophyll content in terms of SPAD reading. Container type had no influence on DW accumulation or leaf area. N concentrations (%) in leaves, roots, and the entire plant increased with increasing N rate. N concentrations in roots and in the entire plant were lower in biocontainers compared with plastic containers. Greater N rate generally increased daily water use (DWU), and biocontainers had greater DWU than plastic containers. The 20 mm N rate resulted in the highest net photosynthetic rate measured on 11 Sept. and 22 Sept. (65 and 76 days after treatment). Net photosynthetic rate (measured on 8 Oct.) and stomatal conductance (gS) (measured on 27 Aug., 22 Sept., and 8 Oct.) were lower in biocontainers compared with plastic containers. Two irrigations per day resulted in higher substrate moisture at 5-cm depth than one irrigation per day, and slightly increased PGI on 19 Aug. However, irrigation frequency did not affect photosynthetic rate, gS, or N uptake of hydrangea plants except in stems. Considering the increased water use of hydrangea plants when grown in the paper biocontainer and lower plant photosynthesis and N uptake, the tested paper biocontainer may not serve as a satisfactory sustainable alternative to traditional plastic containers.

Evaluating On-demand Irrigation Systems for Container-grown Woody Plants Grown in Biochar-amended Pine Bark

Controlling irrigation using timers or manually operated systems is the most common irrigation scheduling method in outdoor container production systems. Improving irrigation efficiency can be achieved by scheduling irrigation based on plant water needs and the appropriate use of sensors rather than relying on periodically adjusting irrigation volume based on perceived water needs. Substrate amendments such as biochar, a carbon (C)-rich by-product of pyrolysis or gasification, can increase the amount of available water and improve irrigation efficiency and plant growth. Previous work examined two on-demand irrigation schedules in controlled indoor (greenhouse) environments. The goal of this study was to evaluate the impact of these on-demand irrigation schedules and hardwood biochar on water use and biomass gain of container-grown Hydrangea paniculata ‘Silver Dollar’ in a typical outdoor nursery production environment. Eighteen independently controlled irrigation zones were designed to test three irrigation schedules on ‘Silver Dollar’ hydrangea grown in pine bark amended with 0% or 25% hardwood biochar. The three irrigation schedules were conventional irrigation and two on-demand schedules, which were based on substrate physical properties or plant physiology. Conventional irrigation delivered 1.8 cm water in one event each day. The scheduling of substrate-based irrigation was based on the soilless substrate moisture characteristic curve, applying water whenever the substrate water content corresponding to a substrate water potential of –10 kPa was reached. The plant-based irrigation schedule was based on a specific substrate moisture content derived from a previously defined relationship between substrate moisture content and photosynthetic rate, maintaining the volumetric water content (VWC) to support photosynthesis at 90% of the maximum predicted photosynthetic rate. Total water use for the substrate-based irrigation was the same as for the conventional system; the plant-based system used significantly less water. However, plant dry weight was 22% and 15% greater, water use efficiency (WUE) was 40% and 40% greater, and total leachate volume was 25% and 30% less for the substrate-based and plant-based irrigation scheduling systems, respectively, than for conventional irrigation. The 25% biochar amendment rate reduced leachate volume per irrigation event, and leaching fraction, but did not affect total water use or plant dry weight. This research demonstrated that on-demand irrigation scheduling that is plant based or substrate based could be an effective approach to increase WUE for container-grown nursery crops without affecting plant growth negatively.

Screening of jute and kenaf varieties for salinity tolerance

A study was conducted in the Department of Agronomy, Bangladesh Agricultural University (BAU), Mymensingh from April to August 2012 to examine the salinity tolerance of eight jute varieties (CVE-3, C-83, CVL-1, BJC-7370, O-795, O-9897, OM-1, O-72) and two kenaf varieties (HC-95 and HC-2). Initially germination of these varieties were evaluated under six salinity levels viz. 0mM, 20mM, 40mM, 60mM, 80mM, and 100mM NaCl in the seed laboratory of the Department of Agronomy. Afterwards, all the varieties was grown in pots in the net house under four salinity levels viz. 0mM, 25mM, 50mM, and 75mM. The results from the germination study revealed that under control condition (0mM NaCl) all the jute varieties showed germination more than 80% both at 7 and at 14 days after seed sowing, whereas kenaf varieties had germination a little less than 80%. Among the jute varieties, O-72 showed the highest germination (92%), which was statistically similar with those of OM-1(91%), O-795 (90%), and C-83(87%). Salinity stress decreased germination drastically in all of the jute and kenaf varieties. A salinity level of 100mM caused the highest germination inhibition (74.70%) in jute variety CVL-1, which was very close to those of BJC-7370 and O-72. On the other hand, the lowest germination inhibition (51.11%) was recorded in jute variety O-795. The results of the pot trail showed that the plant characters of jute and kenaf varieties were affected significantly by salinity stress. All the varieties produced their respective plant height, number of leaves per plant, and plant dry weight under control condition (no salinity). Among these varieties, CVE-3 produced the highest plant height (145.2cm), and total dry weight (22.55g), whereas O-72 produced the highest number of leaves per plant (24.67). All these plant characters decreased sharply due to salinity stress irrespective of variety. However, the rate of decrease of plant characters occurred differentially in the jute and kenaf varieties. The highest rate of decrease in number of leaves (74.22%) was found from the variety CVE-3, whereas the lowest one was recorded from the variety HC-2 (51.68%). Salinity stress caused the highest decrease in total plant dry weight (73.68%) in the variety CVL-1 and plant height (73.64%) also in the variety CVL-1. On the contrary, the lowest decrease in plant dry weight (50.99%) was found in the variety O-9897 and plant height also in variety O-9897 (50.88%). Based on the results from germination test and pot trail, it can be inferred that jute variety O-9897 appeared to be the most salt tolerant followed by O-795, HC-2, HC-95, CVE-3, O-72, C-83, BJC-7370, OM-1, and CVL-1.

Protein Hydrolysate Stimulates Growth in Tomato Coupled With N-Dependent Gene Expression Involved in N Assimilation.

Plant-derived protein hydrolysates (PHs) have received increased attention in the last decade because of their potential to improve yield, nutritional quality as well as tolerance to abiotic stressors. The current study investigated the effects and the molecular mechanisms of a legume-derived PH under optimal and sub-optimal nitrogen (N) concentrations (112 and 7 mg L−1, respectively) in tomato (Solanum lycopersicum L.). Growth and mineral composition of tomato plants treated with PHs by foliar spray or substrate drench were compared to untreated plants. In addition, the expression was determined of genes encoding ammonium and nitrate transporters and seven enzymes involved in N metabolism: nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase 1 (GS1), glutamine synthetase 2 (GS2), ferredoxin-dependent glutamate synthase (GLT), NADH-dependent glutamate synthase (GLS), and glutamate dehydrogenase (GDH). The root and total plant dry weight, SPAD index and leaf nitrogen content were higher by 21, 17, 7, and 6%, respectively, in plants treated by a substrate drench in comparison to untreated tomato plants, whereas foliar application of PH gave intermediate values. PH-treated plants grown with lower N availability showed reduced expression of NR and NiR as well as of nitrate and ammonium transporter transcripts in both leaf and root tissues in comparison with untreated plants; this was especially pronounced after application of PH by substrate drench. Conversely, the transcript level of an amino acid transporter gene was up-regulated in comparison with untreated plants. At high N regime, the transcript levels of the ammonium and amino acid transporters and also NR, NiR, and GLT were significantly up-regulated in root after PH foliar and substrate drench applications compared with untreated plants. An up-regulation was also observed for GS1, GS2, and GDH transcripts in leaf after substrate drench. These results highlighted the potential benefits of using legume PH in vegetable production systems to increase growth and N-nutritional status of plants.