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Abstract Because of the detrimental effects of terrestrial invasive plant species (TIPS) on native species, ecosystems, public health, and the economy, many countries have been actively looking for strategies to prevent the introduction and minimize the spread of TIPS. Fast and accurate detection of TIPS is essential to achieving these goals. Conventionally, invasive species monitoring has relied on morphological attributes. Recently, DNA‐based species identification (i.e., DNA barcoding) has become more attractive. To investigate whether DNA barcoding can aid in the detection and management of TIPS, we visited multiple nature areas in Southwest Michigan and collected a small piece of leaf tissue from 91 representative terrestrial plant species, most of which are invasive. We extracted DNA from the leaf samples, amplified four genomic loci (ITS,rbcL,matK, andtrnH‐psbA) with PCR, and then purified and sequenced the PCR products. After careful examination of the sequencing data, we were able to identify reliable DNA barcode regions for most species and had an average PCR‐and‐sequencing success rate of 87.9%. We found that the species discrimination rate of a DNA barcode region is inversely related to the ease of PCR amplification and sequencing. Compared withrbcLandmatK, ITS andtrnH‐psbAhave better species discrimination rates (80.6% and 63.2%, respectively). When ITS andtrnH‐psbAare simultaneously used, the species discrimination rate increases to 97.1%. The high species/genus/family discrimination rates of DNA barcoding indicate that DNA barcoding can be successfully employed in TIPS identification. Further increases in the number of DNA barcode regions show little or no additional increases in the species discrimination rate, suggesting that dual‐barcode approaches (e.g., ITS + trnH‐psbA) might be the efficient and cost‐effective method in DNA‐based TIPS identification. Close inspection of nucleotide sequences at the four DNA barcode regions among related species demonstrates that DNA barcoding is especially useful in identifying TIPS that are morphologically similar to other species. 

Dark-induced leaf senescence is an extreme example of leaf senescence induced by light deprivation. Prolonged dark treatments of individual leaves result in chlorophyll degradation, macromolecule catabolism, and reduction of photosynthesis. In this work, we described an at-home Dark-induced Leaf Senescence laboratory exercise for a junior-level undergraduate Plant Physiology course. To perform the dark-induced senescence assay on attached leaves, students may cover individual leaves of an outdoor plant with aluminum foils and record the leaf morphology with controlled vocabularies for ~9 days. To perform senescence assays on detached leaves, the students may incubate detached leaves in various aqueous solutions (e.g., tap water, sucrose solution, alkali solution, and acid solution) either in the dark or under natural light, and then record the leaf morphology with controlled vocabularies for ~9 days. This laboratory exercise provides hands-on opportunities for students to understand the relationships among sunlight, chlorophyll, and photosynthesis, in the comfort of students' own homes. Specifically, it helps students to comprehend intrinsic and dark-induced leaf senescence mechanisms, the effects of sugars on leaf senescence, and the importance of optimal pH to plant health. This laboratory exercise can be adapted to support inquiry-based learning or be implemented in a middle or high school classroom. 

Chloroplasts are endosymbiotic organelles derived from cyanobacteria. They have a double envelope membrane, including the outer envelope and the inner envelope. A complex membrane system, thylakoids, exists inside the chloroplast. It is the site of the light-dependent reactions of photosynthesis. The stroma is the main site of the carbon fixation reactions. Although photosynthesis is a very complicated process with many proteins involved, there are many other important processes that occur in chloroplasts, including the regulation of photosynthesis, the biogenesis and maintenance of the structures, carbohydrate, lipid, tetrapyrrole, amino acid, and isoprenoid metabolism, production of some phytohormones, production of specialized metabolites, regulation of redox, and interactions with other parts of the cell (Sabater, 2018). During evolution, most of the cyanobacterial genes were lost and many of them were transferred into the nuclear genome. A majority of chloroplast proteins are nuclear-encoded and possess an N-terminal transit peptide which helps the protein to be targeted into chloroplasts. Chloroplasts have their own highly reduced genome which works coordinately with the nuclear genome for the biogenesis and function of chloroplasts (Liebers et al., 2022). This Research Topic presents studies covering different aspects of chloroplast function, including photosynthesis, biogenesis, structure, and maintenance. These works push the frontiers of chloroplast research further in the field of plant biology.