Botany and Microbiology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
Plant Production Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia; Floriculture, Ornamental Horticulture and Garden Design Department, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria, Egypt; Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, Auckland Park Kingsway Campus (APK) Campus, 2006, South Africa.
Plant Physiol Biochem. 2018 Aug;129:273-284. doi: 10.1016/j.plaphy.2018.06.008. Epub 2018 Jun 9.
Salinity is one of the major agricultural problems that may threat food security and limit the agricultural lands expansion worldwide. Exploring novel tools controlling saline conditions and increase valuable secondary metabolites in the horticultural crops might have outstanding results that serve humanity in the current century. The current study explores the effects of weekly seaweed extracts (7 mLL) and/or 5-aminolevulinic acid (3, 5 and 10 ppm) sprays on Asparagus aethiopicus plants subjected to saline stress conditions (2000 and 4000 ppm) for 6 weeks in two consecutive seasons of 2016 and 2017. Under saline conditions, there were stimulatory synergetic effects of seaweed extracts (SWE) and 5-aminolevulinic acid (ALA) on branch length and number of treated plants. Similar increases were also found in fresh and the dry weight of treated plants compared to control. These morphological improvements associated with increased accumulation of specific phenols (robinin, rutin, apigein, chlorogenic acid and caffeic acid) as revealed by High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD). There were increases in the antioxidant activities of leaf extracts, chlorophyll content and sugars and proline accumulation. The transpiration and photosynthetic rates as well as the stomatal conductance were enhanced. The morphological and physiological improvements associated with increased expression of several genes responsible for water management (ANN1, ANN2 and PIP1), secondary metabolite production (P5CS1 and CHS) and antioxidants accumulation (APX1 and GPX3) in plants. Our findings indicate that SWE + ALA had stimulatory synergetic effects on the growth and secondary metabolites of A. aethiopicus subjected to saline conditions. Several mechanisms are involved in such effects including gas exchange control, sugar buildup, increasing non-enzymatic and enzymatic antioxidants control of reactive oxygen species accumulation as well as transcriptional and metabolic regulation of environmental stress.
盐度是全球农业面临的主要问题之一，可能威胁粮食安全并限制农业用地的扩张。探索控制盐度条件和增加园艺作物有价值的次生代谢物的新工具，可能会在本世纪为人类带来显著的成果。本研究探讨了每周海藻提取物（7 mLL）和/或 5-氨基乙酰丙酸（3、5 和 10 ppm）喷雾对芦笋植物在 2016 年和 2017 年两个连续季节中分别受到 2000 和 4000 ppm 盐胁迫条件下的影响。在盐胁迫条件下，海藻提取物（SWE）和 5-氨基乙酰丙酸（ALA）对处理植物的分支长度和数量有刺激协同作用。与对照相比，处理植物的鲜重和干重也有类似的增加。这些形态学上的改善与特定酚类物质（罗宾素、芦丁、芹菜素、绿原酸和咖啡酸）的积累增加有关，这是通过高效液相色谱与二极管阵列检测（HPLC-DAD）揭示的。叶片提取物的抗氧化活性、叶绿素含量和糖以及脯氨酸积累增加。蒸腾和光合作用速率以及气孔导度增强。与水管理（ANN1、ANN2 和 PIP1）、次生代谢产物生产（P5CS1 和 CHS）和抗氧化剂积累（APX1 和 GPX3）相关的形态和生理改善与负责的基因表达增加有关植物。我们的研究结果表明，SWE+ALA 对芦笋植物在盐胁迫条件下的生长和次生代谢物有刺激协同作用。这些影响涉及多种机制，包括气体交换控制、糖积累、增加非酶和酶抗氧化剂控制活性氧积累以及环境胁迫的转录和代谢调节。
