Effects of walnut husk washing waters and their phenolic constituents on horticultural species

IntroductionThe reuse of wastewaters for agricultural purposes is a common practice in many countries and is increasingly recommended by organizations that promote sustainable development. Yet, it is restricted by the potential negative impact of these materials on soil and crops. The aim of this study was therefore to evaluate the environmental impact of walnut husk washing waters (WHWW) and their organic fractions, in order to conceive their agricultural exploitation.DiscussionPhytotoxicity tests and morphological investigations on representative plant species of horticultural interest indicated that WHWW and their organic fractions can elicit a concentration-dependent stimulating effect on the growth of radish, lettuce cv. cavolo Napoli with effects up to 165 %. An opposite inhibitory effect up to 70 % was observed on spinach and lettuce cv. Gentilina. Proapoptotic effects were observed by acridine orange/ethidium bromide assay in the species inhibited by WHWW treatment. High-performance liquid chromatography–mass spectrometry analysis of the WHWW revealed the presence of a main component which was extracted selectively in organic solvents and purified by preparative chromatography. Complete spectral analysis allowed identification as 4,8-dihydroxy-1-tetralone, commonly known as regiolone. Regiolone exhibited the same concentration-dependent activity on root elongation with a stimulation in the case of radish up to 135 % with respect to control. These results open perspectives in the exploitation of WHWW and the main phenolic constituent readily available by a straightforward isolation procedure as a natural fertilizer for specific crops.

[1]  Inderjit,et al.  Chemical Ecology of Plants: Allelopathy in Aquatic and Terrestrial Ecosystems , 2002, Birkhäuser Basel.

[2]  C. Ciniglia,et al.  ACRIDINE ORANGE/ETHIDIUM BROMIDE DOUBLE STAINING TEST: A SIMPLE IN-VITRO ASSAY TO DETECT APOPTOSIS INDUCED BY PHENOLIC COMPOUNDS IN PLANT CELLS , 2010 .

[3]  S. Jose Black walnut allelopathy: current state of the science , 2002 .

[4]  A. Fiorentino,et al.  Environmental effects caused by olive mill wastewaters: toxicity comparison of low-molecular-weight phenol components. , 2003, Journal of agricultural and food chemistry.

[5]  A. S. Juraimi,et al.  Allelopathic Potential of Rice Varieties against Spinach (Spinacia oleracea) , 2010 .

[6]  Juana Pérez,et al.  Effect of waste waters from olive oil extraction plants on the bacterial population of soil , 1986 .

[7]  Liliana Gianfreda,et al.  Short-term effects of olive mill waste water (OMW) on chemical and biochemical properties of a semiarid Mediterranean soil , 2006 .

[8]  Jacobus P. H. van Wyk,et al.  Biotechnology and the utilization of biowaste as a resource for bioproduct development , 2001 .

[9]  Michael Raviv,et al.  Land spreading of olive mill wastewater: effects on soil microbial activity and potential phytotoxicity. , 2007, Chemosphere.

[10]  Wright,et al.  Three new metabolites from marine-derived fungi of the genera coniothyrium and microsphaeropsis , 1999, Journal of natural products.

[11]  F. A. Macias Allelopathy: Chemistry and Mode of Action of Allelochemicals , 2007 .

[12]  Chen Li,et al.  Simultaneous determination of three diarylheptanoids and an alpha-tetralone derivative in the green walnut husks (Juglans regia L.) by high-performance liquid chromatography with photodiode array detector. , 2008, Journal of chromatography. A.

[13]  B. Vanyushin,et al.  Apoptosis in plants: specific features of plant apoptotic cells and effect of various factors and agents. , 2004, International review of cytology.

[14]  L. Estevinho,et al.  Total phenols, antioxidant potential and antimicrobial activity of walnut (Juglans regia L.) green husks. , 2008, Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association.

[15]  G. Pinto,et al.  Phytotoxicity of Low-Molecular-Weight Phenols from Olive Mill Waste Waters , 2001, Bulletin of environmental contamination and toxicology.

[16]  Oliver Yu,et al.  Metabolic profiling of strawberry (Fragaria x ananassa Duch.) during fruit development and maturation. , 2011, Journal of experimental botany.

[17]  A. E. Hadrami,et al.  Physico-chemical Characterization and Effects of Olive Oil Mill Wastewaters Fertirrigation on the Growth of Some Mediterranean Crops , 2004 .

[18]  Ke-Qin Zhang,et al.  Ymf 1029A-E, preussomerin analogues from the fresh-water-derived fungus YMF 1.01029. , 2008, Journal of natural products.

[19]  S. Talapatra,et al.  (−)-Regiolone, an α-tetralone from Juglans regia: structure, stereochemistry and conformation , 1988 .

[20]  F. Stampar,et al.  Traditional walnut liqueur – cocktail of phenolics , 2006 .

[21]  S. Sayadi,et al.  Polyphenols dynamics and phytotoxicity in a soil amended by olive mill wastewaters. , 2007, Journal of environmental management.

[22]  C. Ciniglia,et al.  Application of Microscopic Techniques to the Study of Seeds and Microalgae under Olive Oil Wastewater Stress , 2003 .

[23]  Ke-Qin Zhang,et al.  Colomitides A and B: Novel Ketals with an Unusual 2,7‐Dioxabicyclo[3.2.1]octane Ring System from the Aquatic Fungus YMF 1.01029 , 2009, Chemistry & biodiversity.