Dissertation objectives included investigating how environment and plant life history influence aspects of leaf vascular infrastructure that supports photosynthesis, as well as photoprotection of the photosynthetic process. Additionally, I aimed to engage students in science and plant biology through innovative teaching methods. In summer annual plants relying on two different pathways to export sugar from the leaf, higher growth light conditions increased photosynthetic capacity coupled with either greater numbers or increased sizes of vascular cells, especially sugar-loading phloem cells. Greater loading-cell numbers presumably favored sugar export in species that relied on sugar transport across membranes. In contrast, larger cells presumably favored intracellular production of the larger sugars used for export by other species. I extended this analysis to species that differed in life strategies as well as sugar-loading pathways. Growing these species under common conditions revealed consistent differences in vascular cell numbers and sizes between summer and winter annuals, with a mix of these vascular features in a biennial species that was active during summer and winter. Moreover, I emphasized the importance of plants for humans by highlighting plant protective mechanisms against environmental stress that also benefit human health. I identified growth environments that optimized production of the carotenoids zeaxanthin (that protects both photosynthesis and the human eye from intense light) as well as lutein and [beta]-carotene (crucial for photosynthesis in various light environments and for human low-light vision). This underscored the importance of a plant-rich diet for human health and emphasized the role of plants in society. Duckweed plants emerged as a unique model for sustainable agriculture due to their rapid growth, resource-use efficiency, and production of high-quality food. I used duckweed as a tool to raise awareness about plant services by designing a case study that illustrates plant services for human society, focusing on duckweed's potential role in regenerative life support systems for long-duration human space missions. After participating in this study, students felt more confident understanding scientific literature, had an increased appreciation for plants and interdisciplinary connections, and improved skills in drawing conclusions from scientific information. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]