Laboratory 1: Plant Vegetative Morphology and Vegetables

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INTRODUCTION

The goals of this laboratory exercise are to familiarize you with the vegetative morphology of flowering plants and to make you more aware of the different types of edible vegetables we use in our daily lives. Leaves, stems, and roots comprise the vegetative body of a flowering plant. Leaves are responsible for photosynthesis. Stems comprise the central axis and branches of a plant, a system which acts to transport photosynthates from the leaves to other organs of the plant and to transport water and nutrients from the roots. The system of stems and branches also serves to get the solar panels of the plant--the leaves--to the light. Together, leaves and stems are often referred to as shoots. Roots serve as anchors, holding the plant upright, and as sponges that extract water and nutrients from the soil. Many roots and stems are also modified for the storage of nutrients. These nutrients are in turn used by the plant to produce new growth.

Over the course of human evolution a diverse array of plant vegetative structures have been selected for their food value. The vegetables we eat today have a long history of artificial selection and cultivation. There was a time in the past when the ancestors of the plants we eat today were gathered from the wild to sustain the lives of our ancestors. Eventually, these wild plants were selected and modified through cultivation to support the growing population of human beings on this planet. We rely on many plant vegetative structures as food for ourselves as well as for our livestock.

By the end of this lab period you should be able to recognize the different vegetative structures of a typical flowering plant and to describe briefly the importance that each of these structures serves in the life of a plant. You should be able to recognize numerous edible vegetables by their common and scientific name and, in general, know what vegetative plant structure is represented by the vegetables on display. You should also gain a basic understanding and especially an appreciation of the diversity of geographic origins of cultivated plants. Stated in other words: we want you to know your food!

ACTIVITY

Can you match the common names listed below with the vegetables displayed? Study the vegetables provided, paying special attention to their morphological structure, family, scientific name, and geographic origin.

 
 

COMMON NAME		FAMILY/SCIENTIFIC NAME		STRUCTURE		ORIGIN
alfalfa sprouts		Fabaceae/Medicago sativa		shoot		Near East
asparagus		Liliaceae/Asparagus officinalis		shoot		Mediterranean
bamboo shoots		Poaceae/Bambusa vulgaris		shoot		Asia
bean sprouts (Mung)		Fabaceae/Vigna radiata		whole plant		Asia
beet		Chenopodiaceae/Beta vulgaris		root		Mediterranean
bok-choi		Brassicaceae/Brassica chinensis		leaf		Asia
brussels sprouts		Brassicaceae/Brassica oleracea var. gemmifera		shoot		Europe
cabbage		Brassicaceae/Brassica oleracea var. capitata		leaf		Mediterranean
cactus pad		Cactaceae/Opuntia sp.		stem		New World
carrot		Apiaceae/Daucus carota		root		Mediterranean
cassava/manioc/yuca		Euphorbiaceae/Manihot esculenta		root		S. America
celery		Apiaceae/Apium graveolens		petiole		Eurasia
chinese cabbage		Brassicaceae/Brassica pe-tsai		leaf		Asia
cinnamon		Lauraceae/Cinnamomum verum		bark		Sri Lanka/India
collard greens		Brassicaceae/Brassica oleracea var. acephala		leaf		Europe
daikon		Brassicaceae/Raphanus sativus cv. Longipinnatus		root		Asia
fennel		Apiaceae/Foeniculum vulgare		stem		Mediterranean
garlic		Liliaceae/Allium sativum		stem		Asia
ginger		Zingiberaceae/Zingiber officinale		stem		Asia
jicama		Fabaceae/Pachyrrhizus erosus		root		Mexico
kale		Brassicaceae/Brassica oleracea var. acephala		leaf		Mediterranean
kohlrabi		Brassicaceae/Brassica oleracea var. gongyloides		stem		Mediterranean
lettuce		Asteraceae/Lactuca sativa		leaf		Eurasia
leek		Liliaceae/Allium ampeloprasum		stem		Near East
maple syrup		Aceraceae/Acer saccharum		sap(stem)		N. America
mustard greens		Brassicaceae/Brassica nigra		leaf		Eurasia
onion		Liliaceae/Allium cepa		stem		Asia
parsley		Apiaceae/Petroselinum crispum		leaf		Eurasia
parsnip		Apiaceae/Pastinaca sativa		root		Mediterranean
radish		Brassicaceae/Raphanus sativus		root		Asia
rhubarb		Polygonaceae/Rheum rhabarbarum		petiole		Asia
shallot		Liliaceae/Allium cepa		stem		Asia
spinach		Chenopodiaceae/Spinacia oleracea		leaf		Asia
sugar cane		Poaceae/Saccharum officinarum		stem		tropical Asia
sweet potato		Convolvulaceae/Ipomoea batatas		root		S. America
swiss chard		Chenopodiaceae/Beta vulgaris var. cicla		leaf		Mediterranean
taro root		Araceae/Colocasia esculenta		stem		Old World tropics
turnip		Brassicaceae/Brassica campestris		root		Eurasia
water chestnut		Cyperaceae/Eleocharis tuberosa		stem		Old World tropics
white potato		Solanaceae/Solanum tuberosum		stem		S. America
yam		Dioscoreaceae/ Dioscorea sp.		stem		Old World tropics

 

STUDY QUESTIONS

1. What are the three main vegetative organs used for dietary purposes?

 

2. Sketch a leaf and label the parts.

 

3. Why are leaves so important to a plant? What purposes do they serve? Why are the leaves of a plant so important to life on planet Earth?

 

4. What are three ways that leaves can be arranged on a stem?

 

5. Draw a compound leaf and a simple leaf.

 

6. How can you tell the difference between monocots and dicots using leaf characteristics?

 

7. What purposes do stems serve in overall plant function?

 

8. Name one similarity and one difference between a carrot and a white potato. Think about function and vegetative structure.

 

9. Asparagus is the Cadillac of all vegetables. What part of the asparagus plant do we actually eat?

 

10. White potatoes are modified stems which grow underground. How can one tell that these vegetables are actually stems and not roots? What purpose does this stem modification serve in overall plant function?

 

11. What is an onion? Name the parts of an onion. What purpose does an onion serve in the overall function of the onion plant?

 

12. 12.You should know by now that each of the vegetables we eat has a wild ancestor. Why might the wild ancestors of the common potato, sweet potato, and carrot have smaller underground organs than the cultivars which are grown by human beings?

 

13. What are two main types of root systems in flowering plants? How do monocot roots and dicot roots typically differ?

 

14. What is a brussels sprout?

 

15. Give the common name of four vegetables in the family Brassicaceae.

 

16. What are two functions of roots?

 

17. Carrots, radishes, and turnips are quite similar in structure and function. What do we call these structures and what is their main function?

 

18. What part of a mushroom do we eat? Is a mushroom a plant?