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.
