scholarly journals The Effect of a Hydrophilic Polymer on Plant Water Status and survival of Transplanted Pine Seedlings

1995 ◽  
Vol 5 (2) ◽  
pp. 141-143 ◽  
Author(s):  
R. Savé M. Pery ◽  
O. Marfà ◽  
L. Serrano

Two experiments were conducted to assess the ability of a water-absorbing synthetic polymer to reduce water stress injury of seedlings of Pinus pinea L. under greenhouse and field conditions. In both experiments, two rates of hydrated hydrogel, corresponding to 200 and 400 cm3 of stored water, and a control treatment without hydrophilic polymer were tested. Survival periods for the pine seedlings were 1.4 and 2.0 times longer for the 200- and 400-cm3 treatments, respectively, than for a control treatment in a greenhouse assay. In the field assay, only differences in seedling survival between both hydrogel treatments and control were measured. Leaf water potential values of control plants were significantly lower than hydrated polymer treatments in both experiments. From these results, we conclude that the use of hydrophilic polymers may be an important method of increasing the success of reforestation in semiarid regions.

2008 ◽  
Vol 38 (4) ◽  
pp. 656-666 ◽  
Author(s):  
Patrick J. Baker ◽  
Andrew P. Robinson ◽  
John J. Ewel

We examined the growth response of Acacia koa Gray (koa) in dense (10 000 trees/ha), ~25-year-old, second-growth stands on Hawai‘i to crown release (thinning) and grass control. Koa diameter increment increased within 2 months of thinning across the range of residual densities (200–900 trees/ha). After 3 years, diameter increment in the most intense thinning treatment was 180% greater than in the control treatment (1.4 vs. 0.5 cm/year); in the least intense thinning treatment diameter increment was 100% greater than the control (1.0 vs. 0.5 cm/year). Koa’s growth response was independent of all measures of tree size (diameter at breast height, height, and leaf area) across the range of tree sizes sampled. A grass control treatment to determine if reduced competition for soil water would improve koa growth showed no improvement in growth response. Koa phyllode δ13C values, which represent an integrated measure of tree water status, showed no evidence of tree water stress (mean δ13C = –28.3‰) and were not significantly different between the grass removal and control treatments. These results demonstrate that koa is capable of responding quickly and positively to crown release despite years of suppressed growth and suggest that landowners interested in managing koa forests may have considerable flexibility in the timing and application of thinning treatments to koa stands.


2020 ◽  
Vol 66 (No. 6) ◽  
pp. 249-256
Author(s):  
Lukáš Hlisnikovský ◽  
Milan Vach ◽  
Zdeněk Abrhám ◽  
Ladislav Mensik ◽  
Eva Kunzová

In the years 2011–2014, winter wheat grain yield, qualitative and economic parameters were evaluated according to different fertiliser treatments: (1) control: unfertilised treatment; (2) farmyard manure (FYM) and (3) FYM + NPK (farmyard manure applied together with mineral NPK). The highest yields (8.10 t/ha) were recorded in the FYM + NPK treatment, while significantly lower yields (6.20 t/ha and 5.73 t/ha) were recorded in FYM and control treatments, respectively. Similarly, statistically significantly higher values of the quality parameters were found in the FYM + NPK treatment (13.55% of crude protein content and 43.56 mL of Zeleny’s sedimentation test), compared to control (10% and 22.44 mL, respectively). The modelling expert system (AGROTEKIS-Crop Technology and Economy) was used for the evaluation of economy. This software is based on technological methods of cultivation and norms of material input costs and costs of individual mechanised works. The economic benefits and profitability were evaluated for three different levels of grain market price. The highest gross profit per ha was recorded in the FYM + NPK treatment. According to the gross profit, the control treatment provided better results than the FYM treatment.


2020 ◽  
Vol 12 (15) ◽  
pp. 2359
Author(s):  
Víctor Blanco ◽  
Pedro José Blaya-Ros ◽  
Cristina Castillo ◽  
Fulgencio Soto-Vallés ◽  
Roque Torres-Sánchez ◽  
...  

The present work aims to assess the usefulness of five vegetation indices (VI) derived from multispectral UAS imagery to capture the effects of deficit irrigation on the canopy structure of sweet cherry trees (Prunus avium L.) in southeastern Spain. Three irrigation treatments were assayed, a control treatment and two regulated deficit irrigation treatments. Four airborne flights were carried out during two consecutive seasons; to compare the results of the remote sensing VI, the conventional and continuous water status indicators commonly used to manage sweet cherry tree irrigation were measured, including midday stem water potential (Ψs) and maximum daily shrinkage (MDS). Simple regression between individual VIs and Ψs or MDS found stronger relationships in postharvest than in preharvest. Thus, the normalized difference vegetation index (NDVI), resulted in the strongest relationship with Ψs (r2 = 0.67) and MDS (r2 = 0.45), followed by the normalized difference red edge (NDRE). The sensitivity analysis identified the optimal soil adjusted vegetation index (OSAVI) as the VI with the highest coefficient of variation in postharvest and the difference vegetation index (DVI) in preharvest. A new index is proposed, the transformed red range vegetation index (TRRVI), which was the only VI able to statistically identify a slight water deficit applied in preharvest. The combination of the VIs studied was used in two machine learning models, decision tree and artificial neural networks, to estimate the extra labor needed for harvesting and the sweet cherry yield.


2021 ◽  
Vol 19 (1) ◽  
pp. 155-163
Author(s):  
S Sapkota ◽  
D Kc ◽  
H Giri ◽  
M Saud ◽  
M Basnet ◽  
...  

The present research was conducted on two factor Completely Randomized Design (CRD) with eight treatments and three replications. A set of experiments were carried out to evaluate the effect of postharvest ethephon treatment and packaging on ripening of mango cv. Maldah. The treatments consisted of ripening agent i.e., ethephon and control treatment under different packaging condition i.e., fiber with hole, fiber without hole, plastic with hole and plastic without hole. The result revealed that different packaging condition and ripening agents influenced the ripening behavior of mango. The highest TSS (15.26), sugar-acid ratio (23.66) and juice content (126.05) were recorded with fiber (without hole) and the lowest TSS (12.60), sugar-acid ratio (9.01) and juice content (116.05) with plastic (without hole). The highest TA (1.44) was recorded with plastic (without hole) and the lowest (0.66) with fiber (without hole). Similarly, the highest BT (2.83) was recorded with fiber (with hole) and the lowest (1.66) with plastic (without hole). Firmness, sweetness, TSS and juice content were the highest with the interaction effect of fiber bag (without hole) and ethephon treatment. In conclusion, mango fruits with ethephon treatment packed in fiber bag (without hole) enhances quality and ripening of mango whereas under controlled condition and without hole plastic packaging mangoes had low quality performance in terms of physio-chemical properties. SAARC J. Agric., 19(1): 155-163 (2021)


2018 ◽  
Vol 48 (10) ◽  
Author(s):  
Adolfo Jatobá ◽  
Klayton Natan Moraes ◽  
Emanuel Fernandes Rodrigues ◽  
Leandro Marcolino Vieira ◽  
Marina Oliveira Pereira

ABSTRACT: The aim of this research was to evaluate the changes in intestinal tract microbiota, hematological parameters and zootechnical indexes of yellowtail lambaris (Astyanax bimaculatus) fed with different probiotic supply frequencies (Lactobacillus spp.). Lambaris (1,200) were distributed in twelve boxes, divided in three treatments, 100% supply; 25% and 0% (control) of feeds supplemented with probiotic. After 87 days, fish fed with supplemented diet, regardless of frequency (100% and 25%), showed an increase in the total lactic acid bacteria count of 7.99±0.15 log CFU mL-1 and 7.04±1, 29 log UFC mL-¹ respectively, in the intestinal tract and decrease of Pseudomonas spp. in both 100% and 25% (4.09±0.84log UFC mL-1 and 4.00±1.12log UFC mL-1, respectively) in relation to the control treatment (6.74±1.04log UFC mL-1). Fish fed with 100% of diets supplemented with probiotics had a higher leukocyte count (47.7±6.7x103μL-1), lymphocytes (36.0±2.6x103μL1), monocytes (12.0±4.2x103μl-1), as well as higher mean final weight (10.60±0.89g) and weekly growth rate (0.80±0.08g.week-1) than the other treatments (25% of probiotic offered and control). Probiotic (Lactobacillus spp.) offered in 25% of feeds (or more) alters the yellowtail lambari microbiota (A. bimaculatus); however, must be offer in 100% of feeds to improve the hematology profile and productive performance.


2018 ◽  
Vol 24 (2) ◽  
pp. 103-108
Author(s):  
Tania Pires Da Silva ◽  
Fernanda Ferreira Araujo ◽  
Fernando Luiz Finger

The objective of this study was to evaluate the growth regulators action on the senescence of wild pansy flowers. In the first experiment, floral stems were treated with ethylene for 24 hours at concentrations of 0.1, 1.0, 10, 100 and 1000 μL L-1 and control without the hormone. In a second experiment, the flowers were immersed in solutions of abscisic acid (ABA) containing 5, 20, 50 and 100 μM for one minute and control with water. In a third experiment, 1-methylcyclopropene (1-MCP) was applied at concentrations of 0.5, 1.0 and 1.5 μL L-1 and control without the chemical. In a fourth experiment, 1-MCP and ethylene were applied, where 1-MCP was first applied followed by ethylene. After the treatments with 1-MCP and ethylene, the floral stems were removed from the hermetic chambers and kept in a vessel containing distilled water at 25 °C, 10 μmol m-2 s- 1 white fluorescent light and 50-70% relative humidity as for the ABA treatment. Flowers treated with ethylene did not present significant differences among the concentrations for visual senescence, showing evidence that this flower is not sensitive to ethylene. Treatment with 1000 μL L-1 of ethylene led to a slightly higher fresh weight loss than other treatments, which had a loss of about 33% at end of the experiment. For the ABA treatment, the flowers showed similar fresh weight loss among the different treatments; however, higher concentrations induced slight senescence of flowers. The use of 1-MCP increased the longevity of wild pansy flowers. These results show that 1-MCP is beneficial in maintaining the flower water status, even in the presence of exogenous ethylene, although ethylene may not be directly involved in the senescence of wild pansy flowers.


2021 ◽  
Vol 117 (3) ◽  
pp. 1
Author(s):  
Fadl Abdelhamid HASHEM ◽  
Rasha M. EL-MORSHEDY ◽  
Tarek M. YOUNIS ◽  
Mohamed A. A. ABDRABBO

<p>Temperature rise is one of the most challenging climate change impacts that increase the intensity of heat stress. In this investigated the production of celery (<em>Apium graveolens</em> var. <em>rapaceum </em>F1 hybrid)) was tested during the late season. The experiment was carried out during the two successive summer seasons of 2019 and 2020 in Giza Governorate, Egypt. The experimental design is a split-plot, the main plots consist of three low tunnel cover treatments, and three spray treatments with three replicates in sub-main plots. Results showed that the use of white net cover gave the highest vegetative growth and yield followed by the black net. Values of plant yield were 951, 765, and 660 g/plant for white, black and without cover, respectively, in the first season. The foliar application of 3 mM of potassium silicate produced the highest vegetative growth and yield compared to the control treatment. Referring to the effect of spray foliar application of potassium silicate on yield 1.5 mM (S1), 3 mM (S2), and control were 892, 795, and 689 g/plant in the first season, respectively. The best combination that delivered the highest vegetative growth and yield was a cover low tunnel with a white net combined with S2 foliar application.</p>


Author(s):  
Tran Thanh Thai ◽  
Pham Thanh Luu ◽  
Ngo Xuan Quang ◽  
Dao Thanh Son

This study aimed to enhance our insight on the potential toxicological effects of silver nanoparticles (AgNPs)  into the aquatic environment. To investigate the chronic toxicity of nanoparticles, freshwater micro-crustacean Daphnia lumholtzi was exposed to different concentrations of 0.2, 0.5 µg/l AgNPs, and control, for 21 days. Toxicological endpoints at different growing stages such as the maturation and reproduction were recorded. The reproduction rate of D. lumholtzi exposed to both AgNPs concentrations (0.2 and 0.5 µg/l ) was significantly lower than that of control. In turn, the maturation exposed to both AgNPs concentrations was not significantly different from the control treatment. This result indicates that AgNPs (with a concentration lower than 0.5 µg/l) did not have an adverse effect on the maturation of D. lumholtzi, but AgNPs with a concentration higher than 0.2 caused a toxic effect on the reproduction rate of D. lumholtzi during 21 days of the exposure period. In conclusion, the present results showed that AgNPs have toxic effects on D. lumholtzi and it has the potential to use as good freshwater aquatic zooplankton for assessment on the toxicity of nanomaterials in tropics. The future study should pay more attention to the effect of AgNPs on survival, growth rate, and multiple generations of daphnids to better understand the effects of nanoparticles in general and AgNPs in particular.


2017 ◽  
pp. 836-853
Author(s):  
N. Suchkova ◽  
E. Darakas ◽  
J. Ganoulis ◽  
Y. Vergeles

In this work the suitability of several plant species for phytoremediation under natural and artificially installed conditions was studied. Brassica napus, Medicago sativa, Zea mays, Triticum aestivum, and Hordeum vulgare were grown in pots with sewage sludge from Sindos Main WWTP in Thessaloniki and from Sindos Industrial WWTP in Thessaloniki, Greece. The first series of experiments included comparing measurements of various parameters for the above mentioned plants and the sludge to those for control samples (the same plants growing in compost). It was shown that shoot growth was less reduced in T. aestivum and H. vulgare than in the other plant species studied. B. napus had lower germination tax, followed by M. sativa with the lowest germination tax. Generally B. napus, giving less biomass production than Z. mays and T. aestivum, is characterised by a higher ability to accumulate heavy metals like Cd, Cu, Ni, Pb, Zn, Cr, As and Hg. The second series of experiments included comparing measurements of various parameters of B. napus grown in sludge and treated each 7 days with metal solutions of Ni, Zn and Pb containing 10-2mg/l, 10-4mg/l, 10-6mg/l of each metal, to those for control plants treated with double distilled water. Results showed that shoot growth of B. napus were increased at treatments with lower concentrations of metals (10-6 mg/l) and control (treatment with d-distilled water). At the same time uptake of metal ions was increased with the concentration of the solution, i.e. at higher concentrations (10-2 mg/l). It is truly for Pb and Zn, transfer coefficient TC of which (indicates a plant’s potential to concentrate a metal) was quite high 15 % and 7 % correspondingly. It was noticed that B. napus has high ability to accumulate Cr, from the other hand it did not accumulate Ni (at present case).


2016 ◽  
Vol 47 (5) ◽  
Author(s):  
K.M. Naser

Laboratory experiment was conducted using silty clay loam soil collected from Agriculture fields in Abu Ghraib to study the release of phosphorus from rock phosphate (10.22 P%) on  a soil treated with three types of organic fertilizers namely; peat moss , sheep manure  , poultry manure and  control treatment (soil only). Ten grams of air dried soil  mixed with 100 mg of ground rock phosphate  and  organic fertilizers added at 2.5% level (w:w) were  incubated at a laboratory temperature (298 K ) after adding  water  up  to two-thirds of the field capacity for 40, 90, 120, 150 and 180 days. Citric  acide  soluble  available phosphorous  was estimated after each incubation periods and kinetic equations used to test its release from treated samples. The additions of chicken manure was the highest in the  amount  of  dissolved phosphorus values followed by sheep manure, peat moss, rock phosphate and control treatment, reaching levels of citric  acide  extractable  phosphorus to  4.2 , 3.8, 3.3, 3.1 and 2.5 mg P kg-1 soil, respectively. The results also showed superiority of first  order equation in the description of phosphorus release from rock phosphate with  release  rate   coefficient  of 3.801 , 3.865 , 4.328 and 4.366 mg P kg -1 soil h-1 for the treatments: soil and rock phosphate only , peat moss, sheep waste and chicken manure, respectively.


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