Name _________________________

Agronomy 505 Exam I 1999

n the space provided write the name of the forage whose leaf tissue or seed are shown (2 points each)

________________ _______________ _______________ ________________

_______________ _______________ _______________

_______________ ______________ ______________ _____________

Fill in the blank with word(s) that best complete the statement (2 points each).

1. Plants that flower more as the days get progressively longer are called _________________________ plants (be specific). A species we have studied with this flowering response is ____________________.
2. The cell wall component that is 100% digestible is _____________________. This cell wall component is more abundant is cell walls of grasses/legumes/no difference between grasses and legumes (circle one).
3. _________________________ is a device that scans the surface of a forage sample and correlates reflected light patterns with forage quality characteristics.
4. Leaf growth of forage grasses occurs in the ____________________________ meristem, while that of dicots occurs in a ________________________________ meristem.
5. Rhizobium meliloti forms effective nodules on ________________________ and ______________.
6. Healthy, functional nodules have a ____________ color because of the presence of ___________________________.
7. ______________________ ice formation is nearly always fatal to plant tissues.

8. _________________________ and ________________________________ are the two most important processes that bringing nutrients to root surfaces.

Select the one choice that best answers the question (2 points each).

0. This mineral nutrient is a cofactor for over 40 enzymatic reactions and is key for promoting good winter hardiness.
1. Na
2. K
3. Co
4. Mo
5. Pb

2. Regrowth of forages occurs as new shoots develop from _________________________ meristems.

1. lateral
2. marginal
3. seminal
4. cartulary
5. axillary

2. As plants harden for winter, the proportion of ___________________ water found in tissue increases.

1. nucleating
2. crystalline
3. bound
4. free
5. amorphous

2. In general, forage grasses rarely accumulate TNC in

1. roots
2. corms
3. stolons
4. rhizomes
5. stem bases

2. In general, herbage availability of C₄ plants exceeds that of C₃ plants during

1. May
2. July
3. September
4. November
5. all of the above

2. A decline in leaf:stem ratio usually is accompanied by

1. advancing maturity
2. increased NDF
3. lower IVDMD
4. lower intake
5. all of the above

2. The largest of the four compartments that comprise the stomach of a ruminant animal is the

1. omasum
2. reticulum
3. rumen
4. cecum
5. abomasum

2. __________________ is the term used to describe the cold treatment required by most grasses before they can flower.

1. phototropism
2. geotropism
3. vernalization
4. cold hardening
5. acclimation

Given the following data on a hay sample calculate the hemicellulose concentration, DDM, DMI, and RFV (show your work). Is this hay more/less/of equal (select one) value when compared to full bloom alfalfa hay? Explain your answer. (12 points).

Crude protein=16%

NDF=47%

ADF=15%

Lignin=7.4%

Draw the leaf of a C₄ plant in cross-section showing at least two vascular bundles and label the following parts: mesophyll cells, bundle sheath cells, phloem, xylem, upper and lower epidermis. Briefly describe what impact does this anatomy have on: a) leaf photosynthetic rates; b) leaf NDF levels and d) bypass protein. (12 points).

a)

b)

c)

On the axis below are the stem base TNC trends for a newly discovered C₃ perennial grass that is harvested three times during the growing season. Would you recommend close mowing of this forage at all three harvests? Why or why not? Explain using our model. What nonstructural polysaccharide are you likely to find accumulating in this species? Why does stem base TNC decline between Nov. and April? (10 points).