| In natural communities of plants, in average about 10% of the production of herbivorous insects has been the trend. The proportion of this loss even overweighs the average proportion in which plant allocated to reproduction and will affect plant fitness. In the face of pressure from Phytophagous insects, plants have evolved a variety of types of defensive measures with respect to physics, chemistry and phenology to reduce the impact of insect feeding. JA (jasmonic acid, JA) and MeJA (methyl jasmonate, MeJA) is a plant signal molecule involved in the defensive responses of plants and are widely present in plants. Exogenous application can stimulate expression of plant defense genes and induce chemical defense. In the last ten years, the research on the JA and MeJA family in the role of plant defense has become a central issue of plant chemical defense. This article materials for the study Cucumis sativus L. and Humulus japonicas, discusses the impact of MeJA induction on plant morphology, biomass allocation and reproduction characteristics, as well as the response levels and costs of the different plants to MeJA induction, which are as followed:1. The research on morphological changes in plant characteristics by inducing after exposed to different levels of MeJA indicates that:(1)the leaf length, leaf width, petiole length, leaf number, leaf area and leaf chlorophyll concentration increase with exposure concentration by induction with exogenous MeJA. The leaf turns bigger,number of leaves increases and content of chlorophyll increases.(2) MeJA induced increased with the concentration of leaf water content decreased as the levels of exogenous MeJA increase. (3) The plant's stem length, stem diameter, internode length and sub-section were lower than the control group after MeJA induction and the plants grew shorter. (4) The plant root length increased with concentration, and root length is longer than the control group after MeJA induction.2. On the plant by applying different concentrations of MeJA induced plant biomass in the study shows that:(1) Application of different concentrations of MeJA treated plants,canse that leaf biomass, petiole biomass and root biomass increased with the concentration increases, but the stem biomass and total weight decreased with the concentration increases.(2) MeJA induced plant root biomass, leaf biomass, leaf stalk biomass increase in the proportion of total biomass, Stem biomass ratio of the total biomass increased with the concentration to 1.2mmol/L, but when the concentration rise to 1.2mmol/L it lower than the control group, Flowers and young fruit weight ratio of the total biomass decreased with increasing concentration, when the the concentration was 4.8mmol/L the proportion of flowers and young fruit biomass in total biomass was the lowest. (3) With the increasing concentration and above ground plants increased the proportion of all treatment groups were higher. However, after the concentration increased to 4.8mmol/L the ground floor and the proportion will decrease.3. After induced by imposed to different concentrations of MeJA, the plant reproduction study shows that:(1) Applying methyl jasmonate induced increased number of flowers. The number of flowers per plant increased with the concentration of MeJA, however, The increase of concentration wasn't proportional to the number of flowers, it increases the concentration of a certain degree of MeJA the number of flower of plant begin to reduced (2) With increasing concentrations of MeJA the number of fruit per plant decreased, but fruit weight increased and was heavier than the control.(3) After MeJA treatment the plant reproductive output, reproductive investment, reproductive efficiency index, reproductive rates and other indicators increased with the increases of concentration of MeJA, but the reproductive indicators decreased with the increase of concentration of MeJA.4. After induced by different concentrations of MeJA, the changes in plant morphology, biomass and reproductive characteristics show that Plants has different responses to different concentration of MeJA.
|
PDF Full Text Request