Plant Growth Is Stimulated by Tea-seed Extract: A New Natural Growth Regulator?

Abstract

<jats:p>Various plant extracts are being marketed claiming to enhance both crop yield and quality and being environmentally friendly. However, these claims are rarely documented by scientific data. In this study, we investigate the growth regulatory effect of Tea Seed Powder (TSP), a saponin-rich waste product from tea seed (<jats:italic>Camellia</jats:italic> sp.) oil production. The product was tested in various concentrations on <jats:italic>Lemna</jats:italic> growth and as a soil and spray application on growth of pot grown beet, mustard, oat, and barley. Finally, two treatments, 0.2 g TSP/L dry soil and weekly sprays with TSP solutions corresponding to 1.5 g TSP/m<jats:sup>2</jats:sup>, were tested for effects on strawberry yield. The results showed significant growth-enhancing effects on the sterile <jats:italic>Lemna</jats:italic> of ≈20% above control, demonstrating that the growth increase was a plant physiological response to TSP rather than an indirect effect of TSP affecting pests and diseases or improving nutrient uptake. Soil-treated, pot-grown beet, oat, and barley plants showed significant biomass increases in the range of 27% to 41% above control at concentrations of ≈0.3 g TSP/L dry soil, whereas increases of 14% to 26% were observed in plants sprayed with 0.15 to 1.5 g TSP/m<jats:sup>2</jats:sup>. Sprayed strawberries had a 38% higher berry yield compared with control plants in 2008, whereas no difference in leaf number and area, number of runners, and inflorescences were detected. In 2009, there were no significant observable differences between sprayed plants and controls. Soil-treated strawberry plants, however, showed a decrease in leaf number in 2008 and in strawberry yield in 2009. The study concludes that TSP has pronounced and direct physiological effects on plants, which can both increase and decrease growth and yield depending on the applied dose. The growth-enhancing effect could be used commercially to improve crop yield; however, because TSP is also known to be very harmful to earthworms, possible environmental effects of the use of TSP in agriculture and horticulture must be considered before use.</jats:p>

Herbicide hormesis – can it be useful in crop production?

“…(C) Berry yield of strawberries in 2008 (C) and 2009 (D) sprayed with extracts of deoiled tea seeds in 2008. The yield in 2009 was not affected by the treatment in 2008, as would have been expected if a trade‐off between present yield and investment in future growth had taken place; significant differences are marked with an asterisk ( t test, P < 0.05); error bars indicate standard error (adapted from Andresen & Cedergreen, 2010).…”

“…The observed beneficial effect on berry yield was however not carried over to the next growing season (Fig. 3C and D) (Andresen & Cedergreen, 2010).…”

“…The results presented have been mainly conducted using two different test systems: (i) a small‐scale laboratory test system using a lettuce ( Lactuca sativa L.) bioassay according to Belz and Cedergreen (2010) as test species and (ii) root application of phytotoxins and more field‐oriented trials conducted with Sinapis arvensis L. (white mustard), Hordeum vulgare L. (barley), or Fragaria vesca L. (strawberry) after spray application and cultivation of plants under controlled (glasshouse), semi‐field (vegetation hall) or field conditions (for experimental details see Belz, 2008; Cedergreen, 2008b; Cedergreen et al. , 2009; Andresen & Cedergreen, 2010). Within these test systems, mainly three phytotoxins have been evaluated, which are as follows: (1) the anti‐auxin PCIB (2‐( p ‐chlorophenoxy)‐2‐methylpropionic acid), as auxins are known to induce hormetic effects (e.g.…”

Herbicide hormesis can act as a driver of resistance evolution in weeds – PSII‐target site resistance in Chenopodium album L. as a case study

“…However, direct hormetic responses in reproductive traits that are not associated with increased vegetative fitness are also indicated. For example, the berry yield of strawberry was increased by 39% without affecting any other plant trait by a weekly spray application of subtoxic doses of de‐oiled tea seed extracts during the growing season . Likewise, hormetic doses of glyphosate were reported to hasten the induction of flowering in plants and upregulate genes related to flowering (reviewed by Brito et al …”

Uses, toxicity levels, and environmental impacts of synthetic and natural pesticides in rice fields – a survey in Central Thailand

“…The results indicate that herbicides diminished competition from native weeds, and (long-term) application of molluscicides presumably protected the crops from snails (while possibly also stimulating rice growth; cf. Andresen & Cedergreen 2010). Golden apple snails were much more abundant in the fields during the wet season (often canals were overflooding), and this may also partly explain the increasing rice densities with greater distance to irrigation canals.…”