Shoot Dry Matter Research Articles

EFFECT OF SALINITY AND POTASSIUM FERTILIZER APPLICATION ON YIELD CONTRIBUTING CHARACTERISTICS OF RICE

Salt tolerant variety BR 41 was grown in kharif 2 season by pot experiment to study the effects of salinity and potassium fertilizer on agronomic characteristics of rice (Oryza sativa L.). The agronomic parameters increased with increasing salinity up to 12 dSm-1 level but with plant height. The increase in tiller number, panicle number, shoot dry matter and total grain yield was statistically significant at 5% (LSD0.05) level, whereas the increase in 1000 grain weight was significant at 1% (LSD0.01) level. Application of potassium fertilizer at different salinity levels did not produce significant change in agronomic parameters with an exception in shoot dry matter.

The role of nitrogen fixation and crop N dynamics on performance and legacy effects of maize-grain legumes intercrops on smallholder farms in Tanzania

Maize-grain legume intercrops form an important component of the cropping systems of smallholder farmers in many parts of sub-Saharan Africa. However, the effects of cropping system and fertilizer use on nitrogen fixation and nitrogen uptake of component crops in maize-legume intercrops are not well understood. Our study addressed the questions: (i) What is the capacity of pigeonpea and lablab to fix atmospheric nitrogen (N2) in sole crop and when intercropped with maize on smallholder farms across different agro-ecological conditions?; (ii) How does productivity and N-uptake by sole and intercropped maize and legumes respond to N and P fertilizer?; and (iii) What are the residual effects of the sole crops, intercrops and fertilizer treatments on the productivity of a succeeding maize crop? We studied additive intercropping systems on eight farms in Babati, Tanzania: maize-long duration pigeonpea, maize-medium duration pigeonpea and maize-lablab, with separate sole crops, at three fertilizer rates: no fertilizer; 40 kg P ha−1; and 90 kg N ha−1 + 40 kg P ha−1. Whereas P fertilizer was applied on maize and the legumes, the N fertilizer was only applied on maize. Maize and pigeonpea were sown simultaneously, while lablab was relay-planted one month later. N2-fixation was quantified using the 15N natural abundance method. N2-fixation differed among the legume species. Sole long-duration pigeonpea fixed significantly more N2 (20–63 kg ha−1 more) than all other cropping systems, corresponding to the greater shoot dry matter and N yield of this system. The combined N uptake of maize and legume in intercrops was consistently larger than that of sole maize or the legume. Application of fertilizer resulted in enhanced N uptake both in the current season (up to 40 kg N ha−1 more) and in a succeeding maize crop (up to 71 kg N ha−1 more). We observed positive associations between grain yield, dry matter production and total N uptake of a succeeding maize crop, and the N-fixed by legume species in the preceding season. Each kg of legume shoot N yield was associated with up to 14 kg ha−1 extra grain yield, 29 kg ha−1 extra dry matter and 0.5 kg ha−1 extra total N uptake of the succeeding maize crop. Our results show that maize-legume intercrops enhance N-uptake. Furthermore, N2-fixation by sole or intercropped legumes confers strong residual benefits on productivity of a succeeding maize crop.

Plant Growth Promoting and Abiotic Stress Tolerant Chickpea (Cicer arietinum L.) Rhizobial Isolates from Some Areas of South Wollo Zone, Ethiopia

Chickpea (Cicer arietinum L) is an important pulse crop prized for its high protein content and is grown as a food source worldwide, including Ethiopia. However, the yield of chickpea is low due to low soil fertility and the ever-changing abiotic stresses. Therefore, this study aimed at isolation, characterization, and selection of chickpea rhizobia effective in their nitrogen fixation and abiotic stress tolerance potential. As a result, 150 nodule samples were collected from three districts of chickpea-producing areas in South Wollo. The nodules were crushed, and the rhizobia were isolated and characterized by using standard microbiological procedures. Based on the presumptive tests conducted, 103 (68.7%) of the rhizobial isolates were tentatively categorized as Rhizobium species. Regarding phosphate solubilization, only 48 (46.7%) solubilized phosphate with a solubilization index ranging from 2.1 to 2.7 mm. Twenty-four (50%) of the isolates were found to be hydrogen cyanide producers. Among the rhizobial isolates tested under greenhouse conditions, 37 (77.1%) of them induced nodulation on their host plant (chickpea). Their symbiotic effectiveness evaluation test confirmed that 16(47.1%), 6(17.6%), 26.47%, and 3(8.8%) were highly effective, effective, low effective, and ineffective, respectively. Of the authenticated rhizobial isolates, 12 (35.5%) of them, including WuCR-15, 16, 17, 18, 19, 20, 23, 30, 31, 32, 36, 38, and 48, accumulated higher shoot dry matter than the positive control. Isolates WuCR- 11, 17, and 36 showed resistance to low and high extreme abiotic stresses of pH, temperature, and salt. Consequently, rhizobial isolates, WuCR- 11, 17, and 36, which were effective and competent in all the tested parameters, were recommended as good rhizobial candidates for applications under greenhouse and field conditions.

Improving potassium use efficiency of sugarcane through the use of polyhalite

BackgroundSugarcane (Saccharum officinarum) is an important crop in the production of food and energy in tropical and subtropical regions. To provide plants with what they need, highly concentrated fertilizers are often deployed which can result in imbalances in plant nutrition. The purpose of this study was to assess the efficiency of polyhalite (K2Ca2Mg(SO4)4·2H2O) as an alternative source of multinutrients for sugarcane compared to single sources of K, Ca, Mg and S.MethodsA glasshouse experiment was carried out on a low-K Entisol from the sugarcane cultivar CV7870. A completely randomized design was used with different K fertilizer management strategies as follows: four K dosages (0, 21, 42 and 63 mg dm−3) associated to distinct sources, namely: polyhalite (PHY); potassium chloride (KCl); potassium chloride+polyhalite in a 1:1 ratio (½KP), and potassium chloride combined with phosphogypsum and kieserite balancing Ca, Mg and S dosages as supplied by pure polyhalite (KGK). Two growth cycles in 6 dm3 soil pots were evaluated: cane plant harvested at 131 days after transplanting, and ratoon harvested at 253 days after transplanting for the determination of dry matter production. Immediately before harvesting in both cycles, leaf nutrient content (K, Ca, S and Cl) was determined using a hand-held X-ray fluorescence spectrometer.ResultsIn general, shoot dry matter and nutrient uptake were higher with the highest K dosage applied and K sources containing Ca and S in the formulation PHY; ½KP; and KGK, for both growth cycles. However, when these sources were provided at the lowest dosage, high agronomic efficiency was observed in all nutrients assessed. Consequently, the cultivar CV7870 was responsive to K application. However, increments in the K dosage resulted in low agronomic efficiency.ConclusionsThis study indicates that PHY is an effective fertilizer for sugarcane farmers seeking to improve nutrient uptake in a low-K Entisol for both cane plant and ratoon. A mix of PHY and KCl is a potential multi-nutrient fertilizer for managing sugarcane production.

Responses of intraspecific and interspecific variations of plant functional traits to grazing in degraded grassland

Understanding the responses of functional trait variation for grassland plants to grazing disturbance is highly helpful to clarify the community assembly mechanism, functional diversity maintenance, plant adaptation and their strategies. We investigated plant functional traits (plant height, root length, leaf area, root area, leaf dry matter content, shoot dry matter content, root dry matter content, specific leaf area, specific root length and root/ shoot ratio) and the responses of their variation characteristics to grazing disturbance in enclosure and grazing grasslands in Horqin Sandy Land. The results showed that the interspecific variation of functional trait was obviously higher than the intraspecific variation in degraded grassland. The relative contribution of interspecific variation to the overall trait variation ranged from 70.2% to 95.1%, while that of intraspecific variation only contributed 4.9% to 29.8%. However, that did not imply the intraspecific variation could be ignored in the community assembly. The interspecific variation in grazing grassland was lower than that in enclosed grassland, while the intraspecific variation increased but the interspecific variation decreased in grazing grassland. Grazing resulted in the decrease of leaf area and leaf dry matter content but the increase of specific root length for pastoral-resistant grasses. However, pastoral-tolerant forbs would improve their dominance in the community by decreasing specific root length and increa-sing leaf area and leaf dry matter content. The traits sensitive to grazing were leaf area, leaf dry matter content, specific root length, and specific leaf area. Leaf traits and root traits were significantly positively correlated within and with each other. Grazing would enhance the synergy of root traits while reduce the synergy of leaf traits. That meant grazing could change the trade-off strategy of functional traits in individual and population levels, and thus affect vegetation structure and function in community level.

Morphophysiological aspects of bean plants cultivated with natural reactive phosphate and solubilizing and growth promoting microorganisms

Beans (Phaseolus vulgaris L.) are an economically important crop, being part of the daily meal of a large part of the Brazilian population. One of the most common problems in bean cultivation is the low availability and low mobility of phosphorus. Among the strategies to improve the acquisition of phosphorus from the soil, the association of plants with microorganisms that promote growth and/or phosphate solubilizers stands out, since the efficiency of phosphate fertilizers depends directly on the microbial action in their cycle. Thus, the objective of this study was to evaluate physiological, morphological and biochemical characteristics in bean plants cultivated with the presence or absence of reactive natural phosphate associated or not with seed inoculation with different efficient microorganisms. The experiment was carried out in a greenhouse with a completely randomized design, consisting of eight treatments and four replications. The treatments were composed of: i) control, and application of ii) Azospirillum brasilense, iii) Bacillus subtilis and Bacillus megaterium, iv) efficient microorganisms (ME), v) reactive natural phosphate (RNP), vi) RNP + A. brasilense, vii) RNP + Bacillus, and viii) RNP + ME. Gas exchange and material collection to determine height, stem diameter, dry matter, acid phosphatase activity and P content were performed 55 days after sowing. The treatment RNP + A. brasilense and other microorganisms contributed to a higher photosynthetic rate and transpiration in bean plants. The treatments RNP + ME and RNP + Bacillus promoted greater plant height and stem diameter, respectively. The shoot dry matter was higher in the RNP + ME treatment, in relation to the other treatments. Acid phosphatase activity was higher in the area of ​​bean plants exposed to reactive natural phosphate, and in the roots of plants exposed to treatment with species of the genus Bacillus. It was possible to verify that the application of microorganisms with natural phosphate, despite not causing an increase in the P content of the shoot, favored the conditions of growth and production of bean plants.

Effects of seed orientation and sowing depths on germination and seedling vigour in Mahua (Madhuca longifolia)

Effects of seed orientation and depth at the time of sowing on germination and seedling vigour of Madhuca longifolia (J.Konig.) J.F.Macbr. were investigated. Seeds with uniform size were sown in sand filled earthen pots at 1.5, 3.0 and 5.0 cm depths, adopting three orientations of the embryo, viz., upright (embryo facing up), horizontal and inverted positions. The experiment was laid out in a completely randomized block design. Percentage germination, days taken for initial emergence, speed of germination, germination index, root and shoot length and dry matter production, vigour index I and vigour index II were calculated. Placing the seeds with the embryo in upright position at a depth of 1.5 cm and 3.0 cm resulted in early and higher germination, higher seedling growth, greater dry matter production and vigour index I and vigour index II.

Grafting enhances drought tolerance by regulating stress-responsive gene expression and antioxidant enzyme activities in cucumbers

Water scarcity is a major limiting factor for crop yield production in arid and water-stressed areas worldwide. Cucumber plants have a high transpiration ratio and are vulnerable to drought. Grafting commercial genotypes onto selected strong rootstocks has been useful in mitigating the effects of drought. Therefore, this study aimed to evaluate the possibility of using a novel rootstock plant’s tolerance to water-deficit stress in inducing drought tolerance in cucumbers by activating the stress-response gene expression and the antioxidant system, which improved the cucumber quality and yield under water-deficit conditions. This field experiment was conducted for > 2 years, 2020 and 2021, with five drought stress tolerant genotypes (i.e., rootstock) and drought-sensitive genotype Luerans (i.e., a scion). They were subjected to various deficit irrigation levels for 12 days, and their agro-physiological and molecular responses to water-deficit stress were assessed. The results of the study showed that the agronomical parameters, including the leaf area (LA), leaf water content (LWC), number of leaves, plant height, root dry matter shoot dry matter, rates of leaf appearance and stem elongation, and total yield significantly increased with grafted cucumber plants than with non-grafted cucumber plants (control) under normal and stressful conditions.Similar results were observed in the physiological measurements in terms of antioxidant enzymes, abscisic acid levels, gibberellic acid content, and lower lipid peroxidation (malondialdehyde, MDA). Grafting of Luerans (section) on five rootstocks significantly raised the activity of antioxidant enzymes (catalase and peroxidase), improved the gibberellic acid and proline accumulation, and reduced the content of lipid peroxidation and abscisic acid. Furthermore, the real-time polymerase chain reaction expression results revealed that transcript levels of the stress-response genes CsAGO1 and CsDCLs increased rapidly and continuously in five rootstock grafting. Concurrently, these findings suggest that grafting with local varieties of novel drought-tolerant rootstock genotypes could improve drought tolerance in drought-sensitive cucumber genotypes.

Determination of The Resistance of Grapevine Rootstocks to Cadmium (Cd) Toxicity

In this study, response of 12 grapevine rootstock genotypes to cadmium (Cd) toxicity were investigated. The Cd application to the soil was made at the beginning of the experiment at 4 different doses. Shoot, leaf and root dry matter yields, leaf Cd, N, P and Zn contents were determined to assess genotype tolerance of Cd toxicity. Present findings revealed that based on shoot, leaf and root dry weights, leaf Cd, N, P and Zn contents, there were Cd-sensitive and resistant genotypes among the present ones. At the greatest Cd dose (Cd20), the greatest Cd contents (µg plant-1) were observed in 8B (6.13), 420A (5.35) and 1103P (4.69) rootstocks and the lowest Cd contents were observed in 99R (1.27) and SO4 (1.58) rootstocks. Among the grapevine rootstocks, SO4 with quite lower leaf Cd accumulation than the other genotypes and increasing shoot and leaf dry weights and leaf N, P and Zn content was identified as resistant against toxic Cd conditions. On the other hand, 8B, 420A, 1103P, 5BB, Harmony genotypes with decreasing shoot, leaf and root dry weights under Cd toxicity conditions, higher leaf Cd accumulations and significantly decreasing leaf N, P and Zn contents were considered as sensitive to Cd toxicity.

Physiological and biochemical characterization of copper-toxicity tolerance mechanism in grass species native to Pampa Biome and Atlantic Forest for use in phytoremediation.

Orchards and vineyards account for significant copper (Cu) accumulation in the soil due to frequent Cu fungicide applications to control leaf diseases. Although grass species are distributed in these areas likely because of their physiological mechanisms to combat Cu toxicity-related stress, the aim of the present study is to identify grass species presenting biochemical-physiological responses that feature adaptive Cu toxicity tolerance mechanisms. Three grass species native to the Pampa and Atlantic Forest biomes (Paspalum notatum, P. plicatulum, and P. urvillei) and an exotic species (Cynodon dactylon) were tested. Plants were cultivated in pots filled with 4kg of typic Hapludalf soil, under two Cu availability, control, and toxicity conditions (80mg Cu kg soil-1). Photosynthetic parameters, relative growth rate, root dry matter, shoot dry matter, the activity of stress-fighting enzymes (superoxide dismutase and guaiacol peroxidase), root biometry, soluble organic carbon, soil pH, and electrical conductivity were evaluated. P. notatum and P. urvillei have physiological characteristics that allow high translocation factor and Cu accumulation in the root and shoot, and it allows their use in phytoremediation processes due to (1) greater activity of stress-fighting enzymes such as POD in the shoot; (2) to larger diameter roots, which allow greater Cu complexation in them - they are lesser sensitive to stress caused by Cu than the other species; and (3) greater soluble organic carbon exudation in the rhizosphere than species P. plicatulum and C. dactylon, which can complex Cu2+ and reduce the presence of forms toxic to plants.

Influence of Different Proportion Intercropping on Oat and Common Vetch Yields and Nutritional Composition at Different Growth Stages

Crop yield mainly depends on environment and cultivation practices that vary according to a growing environment. However, an oat (Avena sativa L.)-common vetch (Vicia sativa L.) intercrop system has not been fully developed in the agro-pastoral ecotone of Inner Mongolia, China. This study evaluated the effects of seven treatments, including five oat-common vetch intercropping patterns, sole oat, and sole vetch on yield and quality performance at different growth periods [75 days after sowing (DAS), 90 DAS, 105 DAS], on the basis of field experiments conducted in the agro-pastoral ecotone of Inner Mongolia in 2015 and 2016. The OV3:1 (oat intercropped with common vetch at seeding ratios 3:1) treatment at 105 DAS in 2016 was superior to other treatments, as it achieved the highest shoot dry matter, increasing by 24.1% and 37.1% compared to sole oat and common vetch. The crude fat (CF) contents, CF yield, and crude protein (CP) yield increased under OV3:1, and acid detergent fiber (ADF) decreased under OV3:1, compared to monoculture. The results indicate that intercropping is an efficient cropping system for the agro-pastoral ecotone of Inner Mongolia. The appropriate proportion of oat and common vetch intercropping at 3:1 and harvesting time not only increases crop yield but also improves the crop quality.

New substrate medium mixture can improve the initial growth of Hylocereus costaricensis (Haw)

Dragon fruit is an exotic species that has currently shown great relevance in the world market. Hence, the demand for materials with high genetic potential has increased. Genetic propagation allows selecting materials with high yield and climatic conditions adaptation. The selection of the substrate influences the quality of the seedling, which should provide adequate conditions for germination and root development. This study aimed to evaluate the seed emergence and initial growth of dragon fruit cultivated in different substrates under nursery conditions. The experiment was carried out in a completely randomized design, with 11 treatments, four replications, and 25 seeds per replication. The treatments used were composed of the soil, mixture with organic compost and commercial substrate. First emergence count, emergence percentage, and emergence speed were evaluated up to 50 days after sowing. Data of shoot length, stem diameter, root length, shoot dry matter, and root dry matter were recorded at 88 days after emergence. The treatment of washed sand + coconut fiber and Tropstrato® provided a higher emergence percentage and emergence speed of dragon fruit seeds. The treatment of coconut fiber + Tropstrato® + organic compost allowed better means for stem diameter, shoot dry matter, and root dry matter. Conversely, the treatments of washed sand + Tropstrato® and Tropstrato® resulted in greater root system growth.

Mixing Hydrogel Granules into Peat Substrate Improves Germination and Enhances Growth and Physiological Performance of Tomato Seedlings

Abstract The effects of hydrogel granules mixed with peat substrate on germination, morphological and physiological parameters of plugged seedlings were tested in tomato seedlings, at two different irrigation regimes. Due to hydrogel presence, the germination speed was increased, whereas mean germination time was significantly reduced. Slight improvement was recorded regarding final germination, but no effect was found regarding the synchronisation index and seedling vigour index. Due to addition of hydrogel granules a significant increase occurred in dry matter of shoots and plants. No effect was found regarding dry matter of roots, but the presence of hydrogel granules significantly reduced the length of tap root. Interestingly, stomata conductance and chlorophyll index were higher than in control plants. No statistically significant interaction was found between hydrogel variants and irrigation frequency, i.e., the effect of different levels of hydrogel variants did not depend on irrigation frequency. Therefore, we recommend mixing hydrogel capsules into the substrate of plug seedlings to improve the morphological and physiological parameters of seedlings and reduce water and fertiliser leaching into the environment.

Trocas gasosas e crescimento do amendoim submetido ao estresse salino e hídrico

ABSTRACT Peanut crops are of great economic interest because their seeds are used as an important source of vegetable protein and edible oil. The objective of this study was to evaluate the physiological indices and growth of peanut crops subjected to saline and water stress. The experiment was conducted in Auroras, Redenção, Ceará, Brazil using a completely randomized split plot statistical design. The plots were composed of irrigation water treatments with varying levels of electrical conductivity - ECw (1.0, 2.0, 3.0, 4.0 and 5.0 dS m-1), while the subplots were formed by the water regimes of 50% and 100% crop evapotranspiration. Plant height, leaf number, shoot dry matter, relative chlorophyll level, transpiration, and leaf temperature were affected by salt stress. The water regime of 100% ETc provided better performance for the variables stem diameter, leaf number, and shoot dry mass of peanuts.

Effect of Phosphate Organomineral Fertilization on the Dry Matter Production and Phosphorus Accumulation of Corn

Brazilian soils are typically highly weathered, naturally poor in P, and rich in minerals with high P-adsorbing capacity. The objective of the present study was to evaluate the efficiency of peat-based granulated organomineral phosphate fertilizer (OMF) on the phosphorus supply capacity, shoot dry matter production and P accumulation of corn plants, as well as its residual effect on soil, compared to that of monoammonium phosphate (MAP). The experimental was performed using a randomized block design with a 2 × 5 + 1 factorial scheme (two fertilizer: OMF and MAP; five P doses: 15, 30, 45, 60, and 75 mg P2O5 dm-3, and one control treatments (no P fertilizer), and three replicates. Two soils (Ferralsol and Planosol) were used in this study. Soil samples were incubated with limestone for 30 days and then dried, sieved and used to fill plastic pots (3 dm3 soil per pot). Four successive corn cultivations were evaluated and, at the end of each cultivation period, the shoot dry mass (SDM) and P content of the corn were determined. In addition, soil P was measured at the end of the experiment. OMF and MAP had similar effects on SDM, but MAP provided higher P accumulation (SPA) of the first two cultivations, while OMF had higher soil residual P in Ferralsol. However, considering the total accumulated in four crops, SDM and SPA were statistically similar between the two P sources. SDM and SPA in Ferralsol increased linearly with increasing doses, while in Planosol, SPA increased linearly with increasing P dose, regardless of the P source, but SDM was not affected by increasing P doses. According to the results, OMF composed of chemically activated peat and MAP can replace MAP as phosphate fertilizer and maintain the same agronomic efficiency.

Seed priming with salicylic acid enhances growth, physiological traits, fruit yield, and quality parameters of cantaloupe under water-deficit stress

Cantaloupe is a nutritive and popular commercial fruit crop. Soil moisture deficit could seriously jeopardize the yield and quality of cantaloupe. Salicylic acid (SA) has a proven role in sustainably mitigating environmental stresses in many plants applied through various methods. A factorial experiment consisting of six SA seed priming doses (non-primed control, 100, 200, 300, 400, and 500 ppm) and three soil moisture regimes (50%, 75%, and 100% field capacity [FC]) was conducted to evaluate the performance of cantaloupe in terms of growth, physiological traits, fruit yield, and quality parameters. The results revealed that severe moisture-deficit condition of 50% FC drastically reduced fruit yield (64%), water productivity (48%), total soluble solids (22%), and membrane stability index (43%), while electrolyte leakage was increased by 260% at the same soil moisture regime compared with 100% FC without any SA application. Plants grown from SA primed seeds exhibited significantly better performance in terms of seed germination traits, growth, physiological, and fruit yield parameters than non-primed plants across soil moister regimes. The performance of cantaloupe in terms of germination rate, root and shoot dry matter, fruit yield, water productivity, total soluble solids content, and membrane stability index was better at 300 ppm SA priming dose, which was statistically similar with 400 and 500 ppm SA doses in most cases. A consistent trend of better performance at 300 ppm SA dose, especially at severe soil moisture-deficit of 50% FC, was observed (48%, 59%, 54%, and 153% higher fruit yield, water productivity, membrane stability index, and net photosynthetic rate, respectively, compared with the non-primed control at the same soil moisture regime). There was almost no effect of increasing SA priming dose above 300 ppm; therefore, this could be regarded as an optimum dose for maximizing productivity and economic returns when cantaloupe is grown under soil moisture-deficit conditions.

Physiological responses of Amaranthus cruentus L. to drought stress under sufficient- and deficient-nitrogen conditions.

Water and nitrogen availability are two major environmental factors that can impair plant growth, and when combined, their effects on plant performance can be either intensified or reduced. The objective of this study was to analyze the influence of nitrogen availability on the responses of Amaranthus cruentus’s metabolism to water stress. The plants were cultivated in plastic pots filled with vermiculite, kept under greenhouse conditions, and were watered three times a week with 70% of a full strength nitrogen-free Long Ashton solution, containing 1.97 or 9.88 kg N ha−1 as ammonium nitrate. Photosynthetic parameters were evaluated in planta, and leaves were harvested for chemical analysis of photosynthetic pigments, proline, and phenolic contents. Higher nitrogen supply increased the shoot dry matter, photosynthetic pigments, photosynthesis, stomatal conductance, transpiration, total leaf nitrogen, proline, nitrate, and ammonium but reduced the concentration of flavonoids and total phenols. Six days of water stress did not affect dry matter, photosynthetic pigments, leaf nitrogen, ammonium, or specialized metabolites but increased the proline under high nitrogen and negatively affected stomatal conductance, transpiration, photosynthesis, relative water content, instantaneous water use efficiency, and leaf nitrate. The negative effect was more pronounced under high nitrogen supply. The results show that the addition of a high amount of nitrogen made the physiological processes of plants more sensitive to water stress, indicating that the plant response to water restriction depends on the interaction between the different environmental stressors to which the plants are subjected.

Soil of the parent plant and AMF mix improve Cerrado’s seedlings growth in forest nurseries

The soil microbiota plays an extremely important role in the growth and survival of plants. The presence of some microorganisms can positively and significantly impact the growth of tree species, which can improve the performance of seedlings after planting for commercial purposes and/or for ecosystem restoration. The present study aimed to evaluate the initial growth of seedlings of Hancornia speciosa and Brosimum gaudichaudii associated with microorganisms from the soil of the parent tree and/or inoculated with arbuscular mycorrhizal fungi (AMF). Four substrates were tested: T1 (control) = Autoclaved dystrophic Red-Yellow Latosol (Aut-dRYL) + autoclaved commercial substrate (Aut-CS); T2 = Aut-dRYL + Aut-CS + inoculum of AMF (Mix); T3 = Aut-dRYL + Aut-CS + soil of the parent plant (SPP); and T4 = Aut-dRYL + Aut-CS + SPP + Mix. The AMF inoculum comprised a mix of the species Gigaspora decipiens, Rhizophagus clarus, and Scutellospora heterogama. Seedling growth was determined 270-350 days after transplanting by measuring the following parameters: mycorrhizal colonization rate (MC), abundance of spores (AS), height (H), stem diameter (D), H/D ratio, volume of roots (VR), dry matter of shoot (SDM), roots (RDM), total (TDM), shoot / root dry matter ratio (SDM/RDM), height / shoot dry matter ratio (H/SDM), and Dickson quality index (DQI). The results showed that the addition of SPP improved the growth and DQI of the seedlings, while the AMF mix minimally changed both growth and DQI. The use of symbiotic microorganisms in the nursery in Brazil is scarse due to the difficulty of acquiring these microorganisms and the lack of commercialization of specific isolates for species native to the Cerrado biome. The present study evaluated the use of soil from naturally occurring areas as a source of inoculum. The higher growth and biomass production of inoculated plants support the use of SPP as a form of inoculum and/or inoculation with native AMF to produce seedlings of H. speciosa and B. gaudichaudii.

Effect of salicylic acid seed priming on morpho-physiological responses and yield of baby corn under salt stress

Rising salinity in the arable lands is a substantial threat to crop production. Exogenously-applied salicylic acid (SA) alleviates the negative impacts of salinity on plants. A factorial pot experiment, consisted of two baby corn hybrid cultivars (PAC 571: salt-tolerant and SG 17 Super: salt-sensitive), three doses of SA (0 [hydropriming], 1, and 2 mM) applied as a seed priming material, and four levels of salinity (0.7 [control], 6, 9, and 12 dS m–1), was conducted to evaluate the impact of SA on baby corn under salt stress. Data on growth, physiological traits, cob yield, and ion content in leaf tissues were collected, which revealed that an increasing salinity level was equally detrimental for the two tested cultivars with varying intensities. At the highest salinity level (12 dS m–1), both cultivars produced no cob, and the same salinity level caused a reduction of 67%, 14%, 42%, 87%, and 37% in shoot dry matter, leaf relative water content, membrane stability index, net photosynthetic rate, and leaf potassium content, respectively, compared with the control across cultivars and SA levels. The same salinity level caused about 3-fold, 10-fold, and 6-fold increases in electrolyte leakage, free proline content, and leaf sodium content, respectively. Seed priming with SA was effective, and 1 mM provided more promising results with an increase of 43%, 45%, 5%, and 7% in root dry matter, cob yield, leaf relative water content, and free proline content at 6 dS m–1 than 0 mM SA at the same salinity level. Salt-tolerant cultivar (PAC 571) had significantly higher cob number plant–1 (30%) and cob yield (34%) than salt-sensitive cultivar (SG 17 Super) at 6 dS m–1. However, there was largely no effect of SA seed priming on other evaluated parameters at 9 and 12 dS m–1 salinity levels. Priming of seeds with 1 mM SA could be a promising approach for baby corn production under a moderate salinity level up to 6 dS m–1. However, harmful effects of extreme salinity (9 and 12 dS m–1) cannot be completely compensated for SA seed priming.

Effect of temperature stress on Brassica rapa genotypes during germination and reproductive growth

The effect of temperature stress on the reproductive development and yield of five Brassica rapa was studied in a controlled growth chamber. The seeds of five Brassica genotypes namely BARI Sarisha-6, Tori 7, Kallayania, BARI Sarisha-9 and BINA Sarisha-4 were grown under day/night temperatures at 22/170C until early flowering or early siliqua development stage. The high temperature stress i.e., 28 /170C or 35/170C, both at early flowering stage and early siliqua formation stage were imposed for 7d and then allowed to recover at 22/170C for normal growth. Shoot dry matter accumulation varied with temperature and genotype. The highest shoot dry matter was recorded by Kallayania followed by BARI Sarisha-9. The optimum day temperature for seed yield of the main shoot showed closer to 280C. The largest seeds were produced in the 22/170C, the size, however, remained similar with 28/170C temperature stress. During this temperature regime, the highest seed yield was observed with BARI Sarisha-6 while BARI Sarisha-9 produced the lowest seed yield. Severe temperature stress (35/170C) reduced seeds per siliqua and 1000 seed weight in all genotypes. Maximum pollen viability and germination were recorded at 200C by Kallayania followed by Tori 7 at 250C. However, the temperature above 300C reduced pollen viability and germination for all the genotypes. In another set of treatments, the high temperatures exposure (28/230C) for 5d reduced oil content and increased protein concentrations. Plant exposed to 25/200C temperature stress showed significant changes in oleic, linoleic, and linolenic acids. The levels of saturated fatty acids were similar across the five genotypes in the control treatment, but palmitic acid and stearic acids increased with the temperature. Bangladesh J. Agri. 2019-2021, 44-46: 19-29