The Effects of Leaf Extracts of Four Tree Species on Amygdalus pedunculata Seedlings Growth

Abstract

Vegetation reconstruction is an urgent problem in fragile environment like coal mine subsidence areas. Amygdalus pedunculata is an important eco-economic shrub species that promotes wind prevention, sand fixation as well as soil and water conservation. The natural regeneration of pure Amygdalus pedunculata forests is difficult to achieve because of its low seed germination rate and weak seedling growth. A stereo-complex ecosystem could potentially promote the germination and seedling growth of A. pedunculata and establish a steady mixed plantation consisting of trees and shrubs. Here, laboratory and pot experiments were conducted to assess the effect of four tree species on morphological and physiological indexes of A. pedunculata. The laboratory experiment showed that A. pedunculata seed germination and seedling growth from Yuyang County (YC-1) and Shenmu County (SC-6) were higher when plants were treated with the aqueous leaf extracts of Pinus sylvestris, Broussonetia papyrifera, and Pinus tabulaeformis compared with Populus simonii at concentrations of 2.5% (E2.5) and 5% (E5). Furthermore, the donor leaf extract was more sensitive to YC-1 than to SC-6. The pot experiment showed that the E2.5 and E5 treatments with the aqueous leaf extracts on the three tree species had strong promoting effects of seedling length, root length, seedling fresh weight, root fresh weight, and ground diameter for YC-1. The activity of catalase of A. pedunculata seedlings first increased and then decreased, while the activity of peroxidase, superoxide dismutase, roots, and the contents of soluble protein and chlorophyll decreased; the opposite patterns were observed for malondialdehyde, soluble sugar, cell membrane permeability, and proline were the opposite. Synthetical allelopathic effect index values of the leaf extracts of the three species on YC-1 were as follows: P. sylvestris > B. papyrifera > P. tabulaeformis (E2.5 to E20). Therefore, P. sylvestris and B. papyrifera could be used to promote the growth of A. pedunculata seedlings as well as for the construction of mixed plantations in coal mine degradation areas. Generally, this study provides new insight into the creation of stereo-complex ecosystems (P. sylvestris + A. pedunculata and B. papyrifera + A. pedunculata) in arid fragile environment.

Enhancement of Interplanting of Ficus carica L. with Taxus cuspidata Sieb. et Zucc. on Growth of Two Plants

“…F. carica could weaken the damage of strong light to T. cuspidata under IFT pattern, which could partly explain the promoting effect of F. carica on T. cuspidata growth under the interplanting pattern. The photosynthetic index under IFT pattern was significantly higher than that of MF, which indicated that there was more dry matter accumulation in the interplanting pattern [27]. In theory, interplanting did not significantly change the light, temperature, water, air, or other ecological factors that might affect the growth of F. carica, so it was speculated that the change of soil factors caused by interplanting pattern was the important factor promoting the growth of F. carica and T. cuspidata.…”

Aqueous Extracts of Three Herbs Allelopathically Inhibit Lettuce Germination but Promote Seedling Growth at Low Concentrations

“…The RI was defined as 1-C/T if T ≥ C or as T/C-1 if T < C, where C and T are the control and treatment values, respectively [61]. The synthetical allelopathic effect index (SE) described the synthesized impact of each aqueous herb extract on L. sativa germination and was calculated as the arithmetic average of the RI of the test items under the same treatment [41,62]. Here, SE = (RI GR + RI SL + RI RL + RI LL + RI LW + RI SB + RI RB )/7, where GR is the germination rate, SL and RL are the shoot and root lengths, respectively, LL and LW are the leaf length and width, respectively, and SB and RB are the shoot and root biomass, respectively.…”

“…In practice, however, there is no apparent pattern in terms of the stimulatory, inhibitory, or hormesis effects of different concentrations of plant extracts. In certain studies, the donor plant tissues were soaked at room temperature (25 • C) for 24, 48, or 72 h [38][39][40][41][42]. The authors believed that the quantity of allelochemical extracted would increase with soaking time.…”

Response mechanisms of sugarcane seedlings to the allelopathic effects of root aqueous extracts from sugarcane ratoons of different ages

“…The decrease in SP content induced by treatment with the root aqueous extract of sugarcane ratoons may have been because allelochemicals in the extract inhibited the absorption of mineral ions by the seedlings, which reduced enzyme activity and protein synthesis. Alternatively, it may have been because the entry of allelochemicals into cells led to the disruption of protein structure, causing a decrease in SP content, or allelochemicals promoted the conversion of SP into SS in seedling tissues and organs to stabilise cellular osmotic potential and enhance the capacity for stress tolerance ( Wang et al., 2021a ).…”