Evaluation of experimental peach rootstocks grown in nutrient solutions for tolerance to iron stress

Author(s):  
M. D. de la Guardia ◽  
A. Felipe ◽  
E. Alcantara ◽  
J. M. Fournier ◽  
F. J. Romera
Author(s):  
M.N. AL-Rukabi ◽  
◽  
V.I. Leunov

Greenhouse tomatoes are divided into early, medium and late-maturing. The days from seedling germination to the first harvest are taken into account. Tomato has a huge potential for heterosis in terms of precocity, overall yield, signs of resistance and uniformity. The preferred agricultural method is hydroponics, which allows you to grow plants without using soil, only using mineral nutrient solutions in water. The cultivation of tomato plants on the " Fitopyramida " will allow to sell their products in the periods with the highest realized prices. An experiment on variety testing of 11 tomato hybrids of different product groups that differ in precocity allowed us to select the most adapted to the conditions of the " Fitopyramida " technology, including the indeterminate beef Ruddy ball F1, cherry hybrids Elf F1 and orange-fruited cherry Magic harp F1. the determinant hybrid Captain F1 showed Good results.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1161f-1161
Author(s):  
John D. Lea-Cox ◽  
Irwin E. Smith

Pine bark is utilized as a substrate in citrus nurseries in South Africa. The Nitrogen (N) content of pine bark is inherently low, and due to the volubility of N, must be supplied on a continual basis to ensure optimum growth rates of young citrus nursery stock. Three citrus rootstock (rough lemon, carrizo citrange and cleopatra mandarin) showed no difference in stem diameter or total dry mass (TDM) when supplied N at concentrations between 25 and 200 mg ·l-1 N in the nutrient solution over a 12 month growing period. Free leaf arginine increased when N was supplied at 400 mg·l-1 N. The form of N affected the growth of rough lemon. High NH4-N:NO3-N (75:25) ratios decreased TDM when Sulfur (S) was absent from the nutrient solution, but not if S was present. Free arginine increased in leaves at high NH4-N (No S) ratios, but not at high NH4-N (S supplied) ratios. Free leaf arginine was correlated with free leaf ammonia. These results have important implications for reducing the concentration of N in nutrient solutions used in citrus nurseries and may indicate that higher NH4-N ratios can be used when adequate S is also supplied.


1975 ◽  
Vol 10 (1) ◽  
pp. 101-109
Author(s):  
H. Kirk Johnston ◽  
H.S. Lim

Abstract The suitability of reverse osmosis as a renovation technique for the treatment of municipal wastewaters has been assessed. Cellulose acetate membranes capable of 70% and 90% NaCl rejections were employed in both laboratory and pilot plant studies to evaluate the efficiency of this technique in removing the residual precipitant chemicals generally employed in phosphorus removal programs (iron chloride, alum, and lime) and the nutrients (phosphates, nitrates and ammonia) characteristic of municipal wastewaters. Secondary sewage and raw sewage as well as prepared nutrient solutions were employed in the course of this program. Both laboratory and pilot plant studies indicated consistently outstanding removal efficiencies for the species examined, almost independent of the nature of the waste solutions being treated. Permeation of the purified effluent was subject to significant reductions due to membrane fouling. This characteristic was most pronounced for the more permeable (less selective) membranes. Routine chemical and physical cleanings enable satisfactory flux levels to be maintained, thereby suggesting that reverse osmosis may become a viable municipal waste treatment technique.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dalila Lopes da Silva ◽  
Renato de Mello Prado ◽  
Luis Felipe Lata Tenesaca ◽  
José Lucas Farias da Silva ◽  
Ben-Hur Mattiuz

AbstractCalcium (Ca) deficiency in cabbage plants induces oxidative damage, hampering growth and decreasing quality, however, it is hypothesized that silicon (Si) added to the nutrient solution may alleviate crop losses. Therefore, this study aims at evaluating whether silicon supplied in the nutrient solution reduces, in fact, the calcium deficiency effects on cabbage plants. In a greenhouse, cabbage plants were grown using nutrient solutions with Ca sufficiency and Ca deficiency (5 mM) without and with added silicon (2.5 mM), arranged as a 2 × 2 factorial in randomized blocks, with five replications. At 91 days after transplanting, the plants were harvested for biological evaluations. In the treatment without added Si, Ca deficiency promoted oxidative stress, low antioxidant content, decreased dry matter, and lower quality leaf. On the other hand, added Si attenuated Ca deficiency in cabbage by decreasing cell extravasation while increasing both ascorbic acid content and fresh and dry matter, providing firmer leaves due to diminished leaf water loss after harvesting. We highlighted the agronomic importance of Si added to the nutrient solution, especially in crops at risk of Ca deficiency.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 616
Author(s):  
Virginia Birlanga ◽  
José Ramón Acosta-Motos ◽  
José Manuel Pérez-Pérez

Cultivated lettuce (Lactuca sativa L.) is one of the most important leafy vegetables in the world, and most of the production is concentrated in the Mediterranean Basin. Hydroponics has been successfully utilized for lettuce cultivation, which could contribute to the diversification of production methods and the reduction of water consumption and excessive fertilization. We devised a low-cost procedure for closed hydroponic cultivation and easy phenotyping of root and shoot attributes of lettuce. We studied 12 lettuce genotypes of the crisphead and oak-leaf subtypes, which differed on their tipburn resistance, for three growing seasons (Fall, Winter, and Spring). We found interesting genotype × environment (G × E) interactions for some of the studied traits during early growth. By analyzing tipburn incidence and leaf nutrient content, we were able to identify a number of nutrient traits that were highly correlated with cultivar- and genotype-dependent tipburn. Our experimental setup will allow evaluating different lettuce genotypes in defined nutrient solutions to select for tipburn-tolerant and highly productive genotypes that are suitable for hydroponics.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1168
Author(s):  
Dimitrios S. Kasampalis ◽  
Danai-Christina Aktsoglou ◽  
Pavlos Tsouvaltzis ◽  
Anastasios S. Siomos

A floating system was established in a heated glass greenhouse in order to investigate whether the effect of amino acids (0.25 or 0.50% of a commercial amino acid (AA) solution Amino16®) during peppermint and spearmint production on plant developmental and nutritional status may be in part attributed to salinity induced osmotic stress. For this reason, in some nutrient solutions, three levels of salinity were induced by adding 0, 10, or 20 mM NaCl. According to the results, it can be concluded that spearmint is mostly favored by the highest amino acid supplement of the nutrient solution (0.50%) in terms of a substantial improvement of the antioxidant nutritional quality (by up to 130%) at the expense of a reduced biomass production (by <30%). Enzymic antioxidant defense mechanism (APX and POD) was efficiently activated, preventing severe lipid peroxidation and the accumulation of reactive oxygen species such as H2O2 and maintaining the proline content at the normal levels. The osmotic stress that was induced by the excessive AA concentration and confirmed by the chlorophyl fluorescence variations was probably related to NH4+ excess supply in the growing media and was not associated with the elevated electrical conductivity in the solution. The absence of any adverse stressful consequences upon the addition of 20 mM NaCl may be attributed to the high salt tolerance of peppermint and spearmint species.


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