BIOL 1030 Lecture Notes - Guard Cell, Transpiration, Turgor Pressure

1. You are an ecologist interested in energetics of ecologicalsystems. You begin your current research program with a study ofprimary productivity of corn plants growing in a field in Iowaduring mid-summer. At noon on a sunny day, you enclose a singleleaf (still attached to the plant) in a transparent chamber. Thechamber is connected to a measurement device called an infrared gasanalyzer, which is capable of measuring minute changes in theconcentration of carbon dioxide (CO2) of the atmosphere within thechamber. The chamber is also maintained at a constant 30°C (same asthe outside air temperature) during your observations. You firstexpose the corn leaf to full sunlight and observe that CO2 is beingdepleted by the leaf from the chamber at a rate of 18 mg CO2 per100 cm2 leaf area per hour. You then cover the chamber withaluminum foil to exclude all light and observe that CO2 is beingreleased by the leaf into the chamber at a rate of 3 mg CO2 per 100cm2 leaf area per hour.

Questions

What is the rate of net primary productivity for this leafduring the measurement period (In mg CO2 per 100 cm2 leaf area perhour)? What is the rate of respiration for this leaf (same units asabove)? What is the rate of gross primary productivityfor this leaf (same units as above)? At this site, cornis planted at a density that results in 75% of the surface beingcovered by leaves. What is the total net primary productivity forone hectare of this corn field (in g C per hectare per year)?Assume that day length averages 12 hours per day over the course ofa 180 day growing season and that your measurement isrepresentative of the NPP for the entire growing season. Show yourcalculations.

Please reword/ rephrase the following in one paragraph thank you

Leaves are determinate structures whose primary function is to produce carbohydrates required for plant growth and development. From a developmental standpoint, leaves are interesting because they display a wide range of genetically and developmentally regulated variation in shape, and because their morphological simplicity and accessibility make them an ideal system for the analysis of basic problems in plant development. Growth control, pattern formation, and cell and tissue differentiation can all be conveniently studied in the context of leaf development. Although many of these problems have yet to be addressed in Arabidopsis, this situation is changing rapidly. This is due in part to the advantages of Arabidopsis for genetic and molecular analysis, but the relatively small size of the Arabidopsis leaf is an equally important advantage of this species because it permits microscopic analysis of an entire leaf at all stages of development.

Like most plants, Arabidopsis exhibits subtle heteroblasty (first described by Röbbelen 1957), in that leaves produced at different stages of shoot development vary in their morphology (Fig. 1). At a gross level, there are two distinct leaf types: rosette leaves and bracts. Rosette leaves are produced early in development and have long petioles and broad blades. Bracts (sometimes referred to as cauline leaves) form at the basal nodes of each branch in the inflorescence and differ from rosette leaves in that they lack petioles and have narrower, more oblong blades.

1a. Ginkgo bilobaThese trees belong to which Phylum?

1b. These trees belong to which Class?

1c. These trees are dioecious (meaning that this species has both male and female trees) The female tree bears fruit. How many of these trees are female and how many are males?

1d. Are these trees deciduous or evergreen?

2a. Examine their leaves and any seed bearing parts. The two trees are:

Sophora japonica, or the Chinese scholar tree or the Japanese Pagoda tree; and the Ouercus robur, or the English Oak tree.

2b. Which tree has pod-like seeds?

2c. These trees belong to which Phylum?

2d. Are these trees deciduous or evergreens?

2e. Identify which tree has a compound leaf and which tree has a simple leaf.

2f. What type of seed does the English Oak produce?

3a. Gleditsia tricanthos These trees belong to what Phylum?

3b. Are they evergreens or deciduous trees?

3c. What type of leaves do these trees possess?

4a. The Northern White Cedar or American Arborvitae.

These trees belong to what Phylum?

4b. Are these trees deciduous or evergreens?

4c. What type of leaves do these trees possess?

4d. These trees belong to what Class?

5a. Pinus strobus This tree belongs to what Phylum and Class?

5b. For the Eastern White Pine can you identify the reproductive organ that this tree produces? Also can find any seeds produced by this tree?

5c. Is the Eastern White Pine a deciduous or evergreen?

5d. What type of leaf do they possess?

6a. Juniperus communis or Common Juniper. This plant belongs to what Phylum and Class?

6b. Can you find any seeds on this plant?

6c. Is the Common Juniper a deciduous or evergreen?

6d. What type of leaf do they possess?

7a. Tilia cordata or American Basswood or little leaf Linden Trees. These trees belong to what Phylum and Class?

7b. Are the leaves of these trees simple or compound?

7c. Are these trees deciduous or evergreen?

7d. Are these trees monocots or dicots? (Look at the veins in the leaves to make this determination)