Fariba Bagheri; Abdolhosein Rezaei Nejad; Mohammad Reza Raji
Abstract
Waterlogging may be imposed by intense rainfall, excessive irrigation, or poor drainage. In Iran, besides the northern parts of the country with high precipitation, waterlogging may occur due to over-irrigation, or inadequate drainage especially for landscape use of ornamentals. In this study, the joint ...
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Waterlogging may be imposed by intense rainfall, excessive irrigation, or poor drainage. In Iran, besides the northern parts of the country with high precipitation, waterlogging may occur due to over-irrigation, or inadequate drainage especially for landscape use of ornamentals. In this study, the joint effects of growth stage (four-leaf stage, full growth and start flowering), at which waterlogging is encountered, and the duration of the episode (0, 6, 12, and 24 h) on flowering induction, plant growth, and external quality were investigated in zinnia (Zinnia elegans Jacq.). Waterlogging generally downgraded visually-perceived quality (stem length, flower size, leaf coloration), increased the risk of buckling (lower stem strength) and shortened flower bud longevity. Waterlogging adversely affected biomass accumulation, through decreases in both light capture (leaf area), and photosynthesis. Besides disturbed water relations, waterlogged plants underwent oxidative damage as indicated by reduced chlorophyll content, and elevated lipid peroxidation level. Waterlogging was further associated with increased activity of antioxidant enzymes (ascorbate peroxidase, peroxidase). The waterlogging-induced effects were generally more prominent as waterlogging duration increased, and the growth stage of application was less advanced, so that the plants waterlogged in four-leaf stage for 24 h showed the most negative effects and their plant dry weight reduced to 75 percent of that in controls. In conclusion, the obtained results offer a quantitative analysis of how both growth stage and duration determine the waterlogging-induced injury in zinnia.
Yasar Akca; Umut Sahin
Abstract
To investigate effects of salinity stress on growth, nutrient status, chlorophyll and water consumption, four different saline irrigation waters (S0= 0.3 dS/m-1 control, S1=1.5 dS/m-1, S2=3 dS/m-1, S3=5 dS/m-1) were applied to two-year Chandler saplings which were grafted on Juglans nigra L. (JN), Paradox ...
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To investigate effects of salinity stress on growth, nutrient status, chlorophyll and water consumption, four different saline irrigation waters (S0= 0.3 dS/m-1 control, S1=1.5 dS/m-1, S2=3 dS/m-1, S3=5 dS/m-1) were applied to two-year Chandler saplings which were grafted on Juglans nigra L. (JN), Paradox (PR) and Juglans sieoboldiana L. (JS) walnut rootstocks. Three different salts including NaCl, MgSO4, and CaCl2 were used to prepare saline irrigations. Shoot length change rate (%) was varied between 77.57 (JN) to 81.83 (PR) for S0 salinity treatments and between 55.60 (JS) to 56.84 (PR) for S3 treatments. The plant diameter change rate (%) varied between 75.10 (JN) to 99.22 (PR) for S0 treatments and 60.63 (JN) to 80.97 (PR) for S3 treatments. Average of root length (cm) was between 30.75 cm (JN) to 37.50 cm (PR) for S0 treatments, and 8.91 cm (JN) to 21.50 cm (PR) for S3. Number of roots changed between 19.00 (JS) to 22.16 (PR) for S0 treatments and between 6.41 (JN) and 8.08 (PR) for S3 treatments. Sodium (Na) content (%) in S3 was 1.41, 1.97 and 3.41 in JN, PR, and JS, respectively. Chloride (Cl-) content (ppm) for S3 was 0.88, 0.99 and 0.91 in JN, PR, and JS, respectively. Ca/Na ratios of 0.43, 0.27 and 0.14 and K/Na ratios of 0.24, 0.12 and 0.10 were detected in JN, PR, and JS, respectively. Depending on leaf Na+, Cl- and K contents, K/Na and Ca/Na ratios, the ranking of salinity tolerance of rootstocks were determined as JN˃ PR ˃ JS.
Li Tao; Zhang Yu-Qi; Zhang Yi; Cheng Rui-Feng; Yang Qi-Chang
Abstract
Chinese solar greenhouse (CSG) is universally applied in northern China for producing horticultural products. CSG is characterized by the unbalanced structures with an arched front roof face to the south side and a thick wall as well as back roof in the north side. Such structures affect light distribution ...
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Chinese solar greenhouse (CSG) is universally applied in northern China for producing horticultural products. CSG is characterized by the unbalanced structures with an arched front roof face to the south side and a thick wall as well as back roof in the north side. Such structures affect light distribution in the greenhouse. This study aims to investigate the light distribution properties in CSG from north to south sections, and to investigate tomato plant growth performance in the corresponding locations. Experiments were carried out in a CSG which was divided into three equal sections from north to south side. Tomato was grown in the greenhouse. Results showed that PAR intensity in the south and middle sections of CSG was permanently higher than the north section. This resulted in a distinct plant growth performance in CSG. Specifically, plants grown in the north section of CSG exhibited a shade avoidance response with stem elongation phenotype and leaf expansion. Furthermore, the north-plants showed lower leaf photosynthetic capacity which correlated with a lower total nitrogen and chlorophyll contents in comparison with the plants grown in the middle and south sections. Taken together, plants in the north section of CSG produced less total biomass than the middle and south section plants. We conclude that plant growth is not uniform in CSG due to heterogeneous light distribution which was caused by unbalanced greenhouse structures. This study may provide sound evidence for exploring a proper lighting strategy as well as fine crop management in CSG.
Mehdi Abdolmaleki; Morteza Khosh-Khui; Saeid Eshghi; Asghar Ramezanian
Abstract
Rosa hybrida L. is an important commercial cut flower. Salicylic acid (SA) and calcium chloride (CaCl2) act as endogenous signal molecules responsible for growth parameters in plants. The aim of this study was to evaluate the effects of preharvest SA and CaCl2 treatments in extending the vase life of ...
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Rosa hybrida L. is an important commercial cut flower. Salicylic acid (SA) and calcium chloride (CaCl2) act as endogenous signal molecules responsible for growth parameters in plants. The aim of this study was to evaluate the effects of preharvest SA and CaCl2 treatments in extending the vase life of cut rose flowers. Therefore, a factorial experiment based on completely randomized design with SA (0, 150, 300, and 450 mg L-1) and CaCl2 (0, 0.75, 1.5, and 2.25%) with 4 replicates and 2 samples (individual flowers) in each replicate, was conducted. Changes in growth, macronutrient concentration, chlorophyll content, leaf relative water content (LRWC), flower quality, vase life, and membrane stability index were investigated in R. hybrida cv. “Dolce Vita.” Exogenously applied SA and CaCl2 increased plant growth (such as shoots and flower buds). Foliar application of SA and CaCl2 also increased macronutrient concentration (N, K, Ca, and Mg), chlorophyll content, LRWC, flower quality, and vase life; however membrane stability index was decreased with increasing levels of SA and CaCl2. These results suggest that SA and CaCl2 could be used as potential growth promoters to improve postharvest life of roses. According to the results of this experiment, SA and CaCl2 as natural, cheap, safe, and biodegradable compounds are suitable alternatives for conventional chemical treatments in order to prolong vase life of cut rose flowers. Commercialization of these compounds for optimum formulations needs further experiments.
