I. Effects of plants on the environment
1) positive impact
This is also the improvement effect of plants on the environment, which basically reflects the existence of these plants in stressed habitats, such as rice grass in saline-alkali land and Populus euphratica in arid environment, which provides good effects on the improvement of saline-alkali land and soil and water conservation in semi-arid areas and has a positive impact on the environment.
2) Negative effects
This is mainly reflected in allelopathy. For example, many plants will import chemicals into the environment after growing, which will affect the growth of other organisms in the environment and ultimately affect the environment in this area. It's like eucalyptus trees in the south. Eucalyptus is planted, there are no birds in the sky and no weeds in the field. Although it meets the aesthetic needs of human beings and cities, it is a kind of destruction to the ecological environment.
3) Neutral action
This is reflected in many crops, such as the research on the obstacles of many related crops, such as the decline of rice yield after several years of continuous cropping, which is basically the result of plants' impact on the environment.
Second, the influence of the environment on plants.
1) positive impact
It is mainly the promotion of the environment to biology, such as the right quota and the right grass. Planting some plants in some places suitable for their growth will undoubtedly promote them, so that even in stressed habitats, such high salinity or drought will provide favorable conditions for the survival of local dominant species to some extent.
2) Negative effects
This is basically the impact of some natural disasters or environmental mutations on plants, so it is not specific.
Third, the harmony between plants and the environment.
The growth of plants affects the environment, and in turn, environmental changes also affect the growth environment of plants. Taking saline-alkali land as an example, the growth of Spartina can significantly improve the salinity of saline-alkali land and ultimately improve the land. The improved environment is suitable for other plants to survive, but it is no longer conducive to the survival and development of Spartina. However, this is our goal, so that plants and the environment can achieve real harmony, which is common in stable habitats, such as many stable ecosystems, such as tropical rainforests, which can basically realize their own adjustment and development without human participation.
This is a general idea, and I hope it will inspire you in your postgraduate entrance examination.