Growth Promotion Effects of Plant Extracts on Various Leafy Vegetable Crops

Abstract

Though the mechanisms are not yet fully understood, the macro-and micro-nutrients, amino acids, and hormone-like growth substances present in plants (whole plants and their extracts) may lead to biostimulatory activities when applied to crops. This study was conducted to determine the growth promotion effects on lettuce (Lactuca sativa L.) of plant extracts obtained by different extraction methods (water, boiling water, fermentation, and ethanol) from 31 agricultural materials. We also determined the growth promotion effects of three other leguminous crop extracts on lettuce. In total, these 31 different agricultural materials produced 82 different extracts. The most effective extracts were water and boiled water extracts of Chinese chive (Allium tuberosum), water extracts of soybean leaves (cvs. Daewon and Haepum), and water, fermentation, and ethanol extracts of soybean stems (cv. Daewon). These induced a 31 -45% increase in shoot fresh weight of lettuce compared with control plants. Chinese chive, soybean leaf, and soybean stem extracts had a greater impact on shoot fresh weight of lettuce when applied at 20 days after seeding (DAS) than when applied at 30 and 40 DAS. In addition, when extracts from Chinese chive and soybean leaf and stem were used, the shoot fresh weight of lettuce was higher at 7 days after treatment (DAT) than at 14 and 21 DAT. The shoot fresh weight of lettuce was 13 -15% higher when the selected extracts were applied twice instead of once. Moreover, the growth promotion effects of the selected plant extracts were also observed in endive and broccoli, but not in pak choi and kale. Additionally, the growth promotion of lettuce was higher in response to soybean leaf and stem extracts than extracts of other leguminous crops (cowpea, mung bean, and red bean). The selected extracts showed higher growth promotion effects on lettuce than those of urea and a commercial extract. Overall, the results indicate that the selected plant extracts can be used for growth promotion in organic cultivation of various crops.

Field efficacy of aqueous extracts of Artemisia annua, Commelina benghalensis and Euphorbia hirta on rice growth, yield and brown spot disease incidence

“…This can be explained by the growth regulators present in the plant extracts that improved the growth variables (Silva et al, 2008;Ijato et al, 2010). Jang and Kuk (2019) reported that plant extracts hade growth promotion effects on various crops, which was corroborated by the current results. The same outcomes resulted with extract from Tephrosia vogelii and Tithonia diversifolia applied as foliar sprays on beans at a concentration of 10% weight per volume, which increased the chlorophyll content, the number of pods per plant bean and the overall seed yield (Mkindi et al, 2020).…”

Growth, productivity and phytochemicals of Coriander in responses to foliar application of Acacia saligna fruit extract as a biostimulant under field conditions

“…In the present investigation, different concentrations of A. saligna FAE had a significant impact on biochemical compounds (antioxidant, flavonoid, total phenolic, and carbohydrates) and total soluble content. In this sense, using biostimulants raised the biochemical components of a variety of leafy vegetables while improving their quality 39 , 96 , 97 .…”

Compounds identified in plant extracts applied to agriculture and seed treatment

“…In the last few years, a growing interest in the application of plant extracts as an alternative to the agrochemicals employment at cropping systems has become a reality (CARMELLO & CARDOSO, 2018;JANG & KUK, 2019;THUERIG et al, 2018;NARASIMHAMURTHY et al, 2019), hence, studies that aim the characterization of the existing compounds in plant extracts used in agriculture, including seed treatment.…”