Search

Stomata are pores in the epidermal tissue of plants formed by specialized cells called occlusive cells or guard cells. Analyzing the number and behavior of stomata is a task carried out by studying microscopic images, and that can serve, among other things, to better manage crops in agriculture. However, quantifying the number of stomata in an image is an expensive process since a stomata image might contain dozens of stomata. Therefore, it is interesting to automate such a detection process. This problem can be framed in the context of object detection, a task widely studied in computer vision. Currently, the best approaches to tackle object detection problems are based on deep learning techniques. Although these techniques are very successful, they might be difficult to use. In this work, we face this problem, specifically for the detection of stomata, by building a Jupyter notebook in Google Colaboratory that allows biologists to automatically detect stomata in their images.

19 pags.- 2 Figs., Together with nitrogen (N), phosphorus (P) has been described as the main plant macronutrient limiting growth. Although P is abundant in many soils, its availability for plants is low. For this reason, P is provided to plants largely through the application of P-enriched fertilizers. However, since rock phosphate reserves (the main source of P) are predicted to be depleted in the near future, it is crucial to understand the processes linked with a better P use efficiency. P is a target structural constituent of energetic compounds (ATP, ADP), nucleic acids, phosphate sugars, etc., that are essential for cell metabolism and plant development. Current knowledge highlights that low P availability negatively affects above- and below-ground organ growth, as a consequence, in part, of poor photosynthetic performance. While essential for all plants, the P requirement of N2-fixing plants has been described as larger than that of non N2-fixing plants, mainly as a consequence of the large P demand for biological N2 fixation (BNF) processes. Moreover, three main factors have been suggested to affect BNF under low P conditions: carbon supply, N-feedback and O2 diffusion have been identified as the main factors conditioning N2 fixation under low P availability conditions. In this chapter, we summarize current knowledge regarding P content in plant performance, with special emphasis on N2-fixing plants and the symbiotic relationship., This work was funded by the Spanish National Research and Development Programme (AGL2014-56561-P), the “I-COOP Suelos y Legumbres” Programme (2016SU0016) and their corresponding FEDER funding, and Aragón Government (A03 research group).

According to global climate model predictions, environmental conditions such as temperature are going to be altered. Plants will be facing high-temperature conditions that affect their development. Within this context, it is crucial to identify the target processes that influence N2 fixation and crop production under elevated temperature conditions. As it is described in this book chapter, while N2 fixation has been well characterized under other adverse environmental conditions (drought, salinity, elevated CO2 concentration, etc.), very little is known about the effect of heat stress on nodule functioning. While there are a few reports about high-temperature effect on nodule carbohydrate and amino acid contents, there is not any study analyzing oxidative stress in those nodules. Regulation of these three factors is essential for optimized N2 fixation; thus, this is a topic that should be studied in more detail. Available information confirms that high temperature strongly affects N2 fixation and plant growth, especially when plants are exposed to temperature higher than 25 °C. High temperature decreased the growth of plants due to its negative effects not only on plants’ photosynthetic performance, but also on nodule growth and development which result in decreased nodule biomass and depletion of nodule total soluble protein content. It is also remarkable that N2 fixation has been showed to be more sensitive to high temperature than photosynthesis. In this chapter, we highlight the variability in performance of various bacterial strains and plant species under high-temperature environments, and discuss about the importance of the identification of target plants and rhizobium cultivars to form optimal symbiotic combinations that will be better adapted to predicted climate change conditions. This in turn will enable higher N2 fixation efficiency and consequently plant growth under adverse environmental conditions, including high temperature.