What efforts has mankind made to control the growth of plants?

In prehistoric times, humans began to recognize and utilize the plant resources around them, such as eating the fruits and rhizomes of wild plants, or using plants to make tools, clothing, and simple shelters. They would identify which plants were beneficial and which were harmful based on observation and experience. Around 10,000 BC, humans began to try to grow crops. The need to obtain food may have been the initial reason that inspired humans to become interested in the mysteries of plant development. With a deeper understanding of the laws of crop growth, humans not only gained a stable food supply, but also laid the foundation for their own development and growth, gradually entering civilization.

Today, although humans have made tremendous progress in the study of plant development and have formed a number of specialized disciplines such as plant physiology, plant molecular biology, and plant ecology, there are still many unknown areas regarding the scientific issue of how plants regulate their growth, and the exploration of this issue has never stopped.

The core of plant development regulation: adapting to environmental changes

The development process and growth cycle of the same animal are basically consistent and limited, but the same plant can show great diversity under different environmental conditions. They will change their morphology to adapt to the environment, such as adjusting the direction of the leaves to maximize photosynthesis, or expanding the root system to obtain water and nutrients, and even adjusting the flowering time to adapt to changing external conditions. This biological characteristic of plants allows plants to adjust their morphology under different environmental conditions. What changes is the appearance, but what remains unchanged is the core of plant development regulation - how to adapt to environmental changes.

One of the reasons why plants can change their morphology is that only a few tissue and organ primordia are produced during embryonic development. During post-embryonic development, new organs all come from the division and differentiation of the apical meristem [1]. This development process is unique to plants, and the molecular mechanism behind this phenomenon has not yet been clarified. Studies have revealed the molecular mechanism of paternal genes in regulating the development of radicle stem cells, which helps us understand the molecular interaction pathways between male and female gametes during fertilization and how these pathways target the formation of embryonic organs [2]. However, further research is needed to understand which genes' expression patterns change during plant organ development and how these changes affect plant morphology and organ development.

Plants have an amazing ability to change their morphology by directly interacting with the environment. Although the factors that regulate plant growth are known, we can only describe the results of growth based on observed phenomena, and how plants perceive and respond to light, temperature, water and nutrition conditions during development is still a process that cannot be analyzed at the microscopic level. These processes are very delicate and dynamic at the molecular level. In theory, the use of molecular biology techniques, gene editing technology, metabolomics analysis, etc. can explore the specific regulatory mechanisms of plant growth at the molecular level, and accurately understand which genes and signal pathways are involved in the growth and development of plants. However, current research results have not yet given a systematic explanation for the developmental regulation of plants.

Research breakthrough: molecular mechanisms of response to environmental changes

Plant development regulation is an extremely complex process involving interactions at multiple levels. Scientists have achieved some important research results and found many valuable research directions. Plant hormones such as auxin, gibberellin, and cytokinin play an important role in plant development. Existing studies have shown that plant hormones play a key role in plant responses to environmental stresses such as drought, salt stress, and heat stress. For example, under drought stress, the accumulation of ABA can trigger plant defense responses, such as stomatal closure and reduced water evaporation [3]. By studying how plants respond to and adapt to environmental stress, we can help reveal the complex molecular regulatory networks that control plant growth and development. These networks include signal transduction pathways, gene expression regulation, and protein interactions. Under environmental stress, some genes may be induced or inhibited, which helps us understand the functions of these genes in plant development. When studying the response of plants to environmental stress, new transcription factors, protein kinases, and other regulatory elements may be discovered, which play a key role in different stages of plant development. Therefore, studying the molecular mechanisms of plant adaptation to environmental stress is of great significance for explaining plant development regulation. Although we have found some breakthroughs in our research, the phenotypic plasticity of plants means that the same genotype may exhibit different phenotypes under different environmental conditions, which brings additional variables to the research, and the complexity of the interaction between plant genotype and environment makes the research more difficult.

A new approach to problem solving based on adaptation

If we can solve the complex problems mentioned above, we will no longer use statistical methods to analyze the phenomenon of plant growth and development. Activities such as planting crops and cultivating seedlings to control plant growth will not be guided by experience alone, but we can apply theories and methods on plant development regulation to allocate resources and accurately control plant growth. For example, in terms of food security, molecular design breeding can be used to breed high-yield varieties, or enhance plant tolerance to high salt or drought conditions, to ensure food production under adverse environmental conditions. In terms of environmental protection, we can better understand the ecological characteristics and success mechanisms of invasive plants, thereby providing a scientific basis for the management and control of invasive plants. We know that plants have a very obvious effect on improving the environment. If plant development becomes a clear and controllable program, it will also help to study how plants survive in harsh environments, and how to improve soil quality and prevent land desertification through plant selection and planting. In addition, by studying the genetic basis and evolutionary laws of plant trait formation, we can reveal the genetic regulation mechanism of plant diversity and complex trait formation, which is crucial for the protection and development of plant germplasm resources.

As more and more genes and their biological functions are revealed during plant growth and development, as well as the mechanisms by which plants respond to the external environment, our research and breakthroughs in the scientific question of how plants regulate their growth will become an important milestone in life sciences.

References:

[1] Weigel D, Jürgens G. Stem cells that make stems[J]. Nature, 2002, 415(6873): 751-754.

[2] Cheng T, Liu Z, Li H, et al. Sperm-origin paternal effects on root stem cell niche differentiation[J]. Nature, 2024: 1-8.

[3] Sun Z, Feng Z, Ding Y, et al. RAF22, ABI1 and OST1 form a dynamic interactive network that optimizes plant growth and responses to drought stress in Arabidopsis[J]. Molecular Plant, 2022, 15(7): 1192-1210.

Author: Zou Huijuan, popular science author

Reviewer: Wang Kang, Director of the North Science Museum of the National Botanical Garden, Professor-level Senior Engineer