Wood Distillate Enhances Growth and Reverses Bioplastic-Induced Stress in Basil Plants

Introduction

Bioplastics, marketed as a sustainable alternative to conventional plastics, are increasingly used in agriculture for applications such as mulch films and biodegradable pots. However, concerns are rising over their impact on soil quality and plant health, as they degrade and release compounds that may hinder plant growth. A recent study published in Science of the Total Environment investigated whether wood distillate (WD), also known as pyroligneous acid, could mitigate the negative effects of starch-based bioplastic on basil (*Ocimum basilicum* L.) plants.

Experimental Design and Application

The study tested four treatment conditions over a 35-day period:

  • Control (C): Basil plants grown without bioplastic or WD.
  • Wood Distillate (WD): Plants received 0.5% (v/v) WD through fertigation once a week.
  • Bioplastic (B): 2.5% (w/w) starch-based bioplastic was mixed into the soil.
  • Bioplastic + Wood Distillate (B + WD): Both 2.5% bioplastic and 0.5% WD were applied.

Basil seeds were germinated and transplanted into glass pots containing a commercial growing medium. WD was applied weekly for four weeks, replacing standard irrigation. The researchers measured plant growth parameters (height, leaf number, fresh biomass), chlorophyll content, and biochemical markers such as soluble proteins, sugars, vitamin C, and malondialdehyde (MDA), an indicator of oxidative stress.

Key Findings

Growth Parameters

Bioplastic significantly hindered basil growth, reducing plant height by 70%, leaf number by 54%, and shoot fresh weight by 90%. WD-fertigated plants exhibited 17% taller growth, 14% more leaves, and 10% greater biomass than control plants. WD also mitigated bioplastic stress, improving plant height by 68%, leaf number by 29%, and shoot biomass by 117% compared to bioplastic-only plants.

Chlorophyll Content

Chlorophyll levels were unchanged in WD-only plants but dropped 19% in bioplastic-treated plants. The B + WD treatment improved chlorophyll content by 7% over bioplastic-only plants.

Biochemical Responses

  • Soluble Proteins: WD-treated plants exhibited 50% higher protein content than the control, while bioplastic reduced protein content by 83%. The B + WD treatment mitigated this reduction, with a less severe 52% decrease.
  • Soluble Sugars: Bioplastic alone reduced sugar content by 41%, while B + WD caused an even greater 66% reduction. WD alone had no significant effect on sugar levels.
  • Vitamin C: WD alone increased vitamin C content by 12%, while bioplastic had no effect. The B + WD combination reduced vitamin C by 33%, likely due to sugar depletion.
  • Oxidative Stress: Bioplastic increased MDA levels by 17%, indicating higher oxidative stress. WD reduced MDA levels by 9% in WD-only plants and by 17% in the B + WD group.

Implications

This study highlights the benefits of wood distillate in promoting plant growth and mitigating bioplastic-induced stress. Findings suggest that WD serves as a promising biostimulant in sustainable agriculture.

Further research is needed to explore WD's long-term effects across different plant species and soil conditions.

Article based on: Exploring Sustainable Alternatives: Wood Distillate Alleviates the Impact of Bioplastic in Basil Plants