SOIL AND PLANT INTERACTIONS (JOURNAL OF SCIENCE AND TECHNOLOGY OF GREENHOUSE CULTURE)
Year:2018 | Volume:9 | Issue:2 (34) |Papers Count:7

Strawberry fruit has very short postharvest life because of its soft texture. To evaluate application effects of amino acids on Post-harvest life of Strawberry fruits, a factorial experiment was carried out based on completely randomized design in Research Greenhouse of Ferdowsi University of Mashhad. Experimental treatments were three amino acids (Arginine, Glutamine and Alanine) at three levels (0, 500 and 1000 µ M) and two cultivars of strawberry (Camarosa and Gaviota). Strawberry fruits were harvested at commercial maturity stage and transported to the laboratory. Then fruits were kept in plastic containers and stored at 4 º C. After 15 days, total soluble solids (TSS), titrable acidity (TA), flavor index (TSS/TA), total anthocyanin, total phenol, phelavonoid, total antioxidant capacity and percentage of fruit weight loss were determined. Results showed that the highest flavor index (18. 41) was observed in Alanine1000-cultivar Gaviota. Also, the lowest fruit weight loss was related to Alanine 500-cultivar Gaviota (18%) and Arginine 500-cultivar Gaviota (14. 5%) treatments. These two treatments were not statistically different. The highest fruit-weight loss (65. 5%) was observed in Glutamine 500-cultivar Gaviota. Also, Glutamine 500-cultivar Gaviota had the highest Antocyanine. It can be concluded from this experiment that application of Arginine and Alanine amino acids prior to harvest of strawberry fruits can increase their postharvest life and quality.

Magnesium plays a key role in photosynthesis, partitioning of carbohydrates, phloem export of sucrose, photo-oxidation and leaf chlorosis of plants. In order to evaluate the effect of various concentrations of Mg (0 (control), 2 and 4 mM) in the nutrient solution and root zone temperature (RZT) (15, 25 and 35 º С ) on growth, yield and physiological properties in cucumber (Cucumis sativus L. cv. Nagen 792) grown in hydroponic system, an experiment was carried out as factorial based on randomized complete blocks design with four replications, in 2014. Results showed that zero Mg treatment (control) significantly decreased leaf fresh and dry weights, number of leaves, leaf area and SPAD index; but remarkably increased shoot to root ratio. These effects were more pronounced when control treatment was combined with RZT of 35º С . The highest yield (578 g per plant) was observed in plants treated with concentration of 4 mM Mg and 15 º С RZT. The lowest yield (276 g per plant) was obtained under concentration of 2 mM Mg and 35 º С RZT. The Fv/Fm value increased with the increase of Mg concentration in the solution and with the decrease of root temperature. Increased Mg concentration in the nutrient solution increased leaf Mg and root phosphorus (P) content. Leaf P content increased as RZT increased. Whereas, root P content decreased as RZT increased. It can be concluded from the results of this research that increasing Mg concentration in the solution decreased the adverse effects 35 º С RZT. Therefore, Mg concentration of 4 Mm in the solution and 15 º С RZT can be considered as an appropriate treatment for hydroponic cucumber cultivation.

The effect of salt stress on morphological and essential oil content of 10 Iranian and foreign Achillea millefolium genotypes was investigated in a pot experiment in Research Greenhouse of Isfahan University of Technology in 2014. The factorial experiment, based on randomized complete blocks design, was performed at four salinity stress levels (0, 5, 10 and 15 dS/m) andn ten Achillea millefolium genotypes with three replicates. Results revealed that salinity stress of 15 dS/m significantly decreased the plant height, leaf area and width, length of ligulate florets, flower diameter, number of florets in inflorescence, days to flowering, days to 100% flowering and dry weight of the herbs. The salinity stress at 15 dS/m increased essential oil content by 18. 75% compared to control treatment. The UK, Slovenia, Spain, Japan, Kandovan (Iran) and Lorestan (Iran) genotypes were not able to produce flowers in high salt stress conditions. The interaction of salinity stress and genotype was significant for all traits except for leaf width and length of ligulate florets. The US and Canada genotypes possessed the highest essential oil content and dry matter weight. The US and UK genotypes can be suggested for green space, under salinity stress conditions, due to their low height and high flower diameter. Most of the studied traits did not show significant differences at 5 and 10 dS/m salinity stress levels. Plants had good resistnce to 10 dS/m salinity stress. Moreover, evaluated traits of plants were significantly different at 15 dS/m level. Based on the obtained results, the 10 dS/m salinity level can be suggested to cultivate this plant.

In vitro production is one of the fast and low-cost methods for mass propagation of horticultural crops. But, in vitro plantlets are more sensitive than others and need more adaptation against climatological factors. In order to investigate the symbiosis effects of two species of mycorrhizal fungi on growth and yield of sweet pepper (Capsicum annum L. ) cv Inspiration, under drought-stress conditions, two separate experiments were conducted. In the first experiment, effects of in vitro inoculation of plantlets of sweet pepper with two species of arbuscular mycorrhiza (G. fasciculatum and G. intraradicese) were evaluated. Results indicated that growth of mycorrhizal-inoculated plantlets were higher than THAT OF HTE control plants. In the second experiment, mycorrhizal-inoculated and non-inoculated sweet pepper plantlets were subjected to three drought-stress levels (100, 75 and 50% of field capacity moisture content). Results indicated that by increasing the drought stress, number of branches, leaf area, chlorophyll content, stomatal conductance, colonization percent and phosphorus content were decreased and potassium and proline content of leaves were increased. Inoculation with G. intraradicese mycorrhiza fungi increased number of leaves, chlorophyll content, fresh and dry weight of fruit and reduced proline content. In general, according to the results of this experiment, symbiosis with mycorrhizal fungi in 75% of irrigation water requirement is appropriate to achieve an acceptable yield, as well as saving water, in cultivation of sweet pepper plant.

Soil amendments have been widely used in greenhouse cultivation. Cucumber, as an important summer crop, has the highest area under cultivation in the greenhouses of Iran. For this reason, in the present research, effect of applying zeolite and drought stress on cucumber growth and its fruit parameters (number, weight, length and diameter of the fruit) was investigated in a split-plots experiment, based on completely randomized design, with 9 treatments and 3 replications, in Arian city, Southern Khorasan province, Iran. Three levels of drought stress (0, 25% and 50% of water requirement), as the main plots, and three levels of zeolite (0, 5 and 10 grams per kg of soil), as the sub-plots, were applied during the plant’ s growing season. Results showed that application of zeolite didn’ t have significant effect on number of fruits; but its effect on other yield parameters (fruit weight, fruit length and fruit diameter) was significant at 5% level. Interaction between water stress and zeolite was significant. Application of 10 grams of zeolite per kg of soil resulted in the highest yield, number of fruits and fruit length. Increasing the amount of zeolite, increased fruit yield.

Plants are faced with various environmental stresses during their growing period. Each of these stresses have different effects on growth, metabolism and yield according to the sensitivity level and stage of the plant growth. One way of reducing the negative effects of the stresses is to use humic substances. The present study was carried out to evaluate the effects of humic acid and drought stress on morphological and physiological indices of marigold. The experiment was carried out according to the factorial arrangement, based on completely randomized design with three replications, in Department of Horticultural Science, Arak University, in fall and winter of 2016. The effects of four humic acid levels (0, 50, 100 and 250 mg/L) and three irrigation intervals (5, 10 and 15 days) was investigated on physiological and morphological traits of the marigold (root length, number of leaves and flowers, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, phosphorus, calcium and proline contents). Results showed that root length and proline content was increased by increasing intensity of drought stress. The highest proline content was obtained by 15-day irrigation interval without humic acid and the lowest content was obtained by 5-day irrigation interval with 250 mg/L humic acid. However, drought stress reduced number of leaves and flowers, chlorophyll (a, b and total), carotenoid, and phosphorus and calcium contents. Higher levels of humic acid, particularly 250 mg/L, increased the amount of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, phosphorus content, root length, number of leaves in the sixth week and number of flowers; but reduced the calcium and proline contents. The 250 mg/L humic acid treatment not only reduced the negative effect of drought stress, but also was able to improve the physiological and morphological characteristics. In conclusion, using humic acid, especially at higher concentrations, is recommended for increasing the irrigation interval of marigold flower.

This study was aimed to evaluate the possibility of using enriched vermicompost with salt-tolerant strains of Streptomyces as a bio-fertilizer in growth and nutrition of cucumber under salinty stress. For this purpose, a pot experiment was set up in a completely randomized factorial design with three replications. Treatments included different salinity levels (0, 30, 60 and 90 mM sodium chloride) and vermicompost (control, unenriched vermicompost and enriched vermicompost with S. rimosus and S. griseus). Results showed that salinity stress caused a significant reduction in the root and shoot dry matter yield, nitrogen, potassium, iron and zinc concentration and potassium: sodium ratio, but increased sodium concentration and cell membrane permeability. Under these conditions, application of vermicompost maintained the structure of cell membranes, improved balance of nutrients and thus reduced the adverse effect of salinity on the plant yield. The effect of vermicomposts enriched with S. griseus and S. rimosus on maintaining root membrane permeability, improving plant nutrition and increasing salt tolerance of plants was more than unenriched vermicompost. So that the highest root and shoot dry weight in salinity of 90 mM NaCl was observed in vermicompost treatment enriched with S. rimosus. According to the results of this study, vermicompost enriched with salt-tolerant strains of Streptomyces, in addition to maintaining the balance of nutrients in saline conditions, improves morphological and physiological characteristics of cucumber plant and thereby can alleviate the damage induced by salinity stress.