Macro nutrients which most effect flavor include the lipids (fats/oils) which effect richness yet mask other flavors, carbohydrates (sugars, starch) which effect sweetness and particular protein constituents, which effect umaminess. Other micronutrients effect sourness and bitterness and modulate the other flavor components. For example, calcium can increase perception of sweetnesss. Soduim content effects saltiness, though other constituents can mask and enhance saltiness.
Aromatics, allelochemicals and other phytochemicals with culinary significance tend to be most prominant in the herbs and spices. Leaves (herbs) and spices (seeds, roots, bark, leaves {including modified such as flowers}) often have protective chemicals to ward off insects, microbes, other plants, fungus and other animals. A subset of these are significant for flavor. Some of the antimicrobial (antibacterial, antiviral, etc.) activity is the reason for medicinal and/or potential toxic overdose potential for some of these. See Natural Plant Science for more information.
Different parts of a plant have different functions and tend to have different amounts of macro and micro nutrients. Then, depending on the plant, there are subcategories that can be made based on typical macro-nutrient content. A useful strategy is to roughly categorize plant parts into
seeds: seed_grain: rice amaranth kamut quinoa millet Oats Sorghum Teff rye Spelt barley buckwheat wheat wheatgerm corn seed_legume: adzuki beans peanuts lentils garbonzo beans (chic peas) fava beans (broad beans) navey beans black (turtle) beans pinto beans lima beans small red beans kidney beans white beans soybeans peas Black-eyed pea Mung bean seed_oil: wheatgerm sesame seed sunflower seed poppy seed (spice) celery seed (spice) chia seed (spice) fenugreek seed (spice) pumpkin seed hemp seed almonds hazelnuts peanuts wallnuts peacons cashews Pine nuts root root_starch: carrot beet rutabaga turnip burdock Celeriac Daikon Yam Parsnip parsley root Radish - sweet potato sunchoke potato root_spice: radish horse radish ginger turmeric ginseng Shallot garlic onion spring onion leaf leaf_bulk: chard beet greens collard greens Turnip greens kale spinach parsley basil cilantro lettuce Dandelion Endive Escarole Fenugreek Kohlrabi greens broccholi Cabbage cauliflower Leek spring onion Mustard greens watercress radicchio spirulina spearmint peppermint Oregano leaf_fine: parsley basil Oregano cilantro spring onion Rosemary Thyme marjoram (spice) savory (spice) spearmint peppermint fruit fruit_veg peppers tomoatoes Tomatillo zucchini yellow Squash winter squash Avocado Cucumber Eggplant fruit_sweet grapes grapefruit apples pears peaches oranges raspberry blueberry strawberry mango banana kiwi lemon lime Fig dates apricot melon