Narrow Results

The Cr${}^{3+}$-activated phosphor can emit far-red light under the excitation of an external light source, mainly due to the transition of the outermost electrons of Cr${}^{3+}$ from the ²E level to the ⁴A₂ level in a strong crystal field environment. A novel far-red Li₂TiO₃: Cr${}^{3+}$ phosphor was prepared by the solid-state method. Under the excitation of 356nm, the Li₂TiO₃: Cr${}^{3+}$ phosphors emit intense far-red light in 600–850nm with a central wavelength of 732nm. The emission band of all samples was matched with the absorption bands of phytochrome P${}_{FR}$. The experimental data and theoretical calculation confirmed that Cr${}^{3+}$ is surrounded by a strong crystal field environment. The effect of Cr${}^{3+}$ doping concentration on the luminescence intensity was analyzed. These research works demonstrate that far-red Li₂TiO₃: Cr${}^{3+}$ phosphors have potential applications in plant growth lights.

This paper has been motivated by the following ecological question: how influential is the water stress on plants production? The aim of this paper is to investigate the impact of water stress and irrigation on plants production. We propose a mathematical model for the dynamics growth of plants that takes into account the concentration of available water in the soil, the absorption of water by plants, water stress, the plants production and the plants compensation. We present the theoretical analysis of the model. More precisely, we show that the model is well-posed. We also compute trivial equilibria and derive a threshold parameter that determines the outcome of water stress within a plantation. Further, we perform a numerical simulation in the case of banana-plantain plant to support and valid theoretical results. We found that the Hopf bifurcation occurs for a specific value of the water absorption rate of unstressed plants. The impact of the water stress on the banana-plantain production is also numerically investigated. We found that the water stress can cause about $62.57\%$ tons of loss of banana-plantain production within a plantation with 1600 rejects initially planted. We also consider the irrigation as a control parameter of water stress. We found that the irrigation increases the stressed plant production to more than $60\%$ for $1600$ rejects initially planted. This suggests that climate change may play a detrimental role on banana-plantains production. We also investigate the role of the type of soil in banana-plantain production. Our finding suggests that the Fine Sandy Loam soil is more resilient to water stress than Silty Clay and Loamy soils.

In order to evaluate and recognize plant growth automatically based on photos of plants in plant science and engineering, we propose a diagnostic system for plant growth in which simulated plant growth is used as a reference for real growing plants. In our diagnostic system, we employ the Lindenmayer system [Lecture Notes in Computer Science, 15, 53–68, 1974] to model healthy growing plants. In the Lindenmayer system plant growth is expressed by string expressions designed as a numerical model for the plant. This proposal system provides users the string expressions by using image processing. As users compare with two strings such as DNA sequence genetic code, users obtain developmental change of plat growth. The results show that our automatic plant diagnostic system is effective in checking actual healthy plant growth, and suggest that the diagnostic system should be useful in large-scale plant factories.

The study of soil-to-plant transfer of radionuclides has attracted considerable attention from a large number of researchers because of the continuous pollution of soils and the effects of radionuclides on plants. In addition, it is one of the important routes for radionuclide entry into the food chain, leading to humans’ exposure to radiation. This chapter focuses on the influence of radionuclides on plant growth, with a particular emphasis on the ratio of these substances in soil and plants concerning nutrition. It is shown in this review that physical and chemical processes and biological accumulation influence the uptake and fate of radionuclides in plants. It is reported that soil contamination by radionuclides affects plant survival rates and inhibits their growth. The effects of radionuclides on plant growth depend on the type of plants, soil properties, initial radionuclide concentration in the soil, and the duration of exposure for the plants. However, some plants have developed radionuclide tolerance mechanisms and accumulate a significant amount of radionuclides, making them suitable for soil remediation.