Download presentation
Presentation is loading. Please wait.
1
Dust Bowl ---> Could this Happen Again??
Figure 37.1 Could this happen again?
2
Soil horizons A horizon B horizon Figure 37.2 Soil horizons C horizon
3
Cation exchange in soil
Soil particle – – K+ K+ – – – – – – – Ca2+ Ca2+ Mg2+ K+ H+ H2O + CO2 H2CO3 HCO3– + H+ Figure 37.3 Cation exchange in soil Root hair Cell wall
4
Land subsidence caused by excessive removal of groundwater
Figure 37.4 Land subsidence caused by excessive removal of groundwater Sinkhole in Florida Land subsidence in California
5
Contour tillage helps reduce soil erosion
Figure 37.5 Contour tillage
6
Hydroponic culture - used by researchers to determine which chemical elements are essential
TECHNIQUE Figure 37.6 Hydroponic culture Control: Solution containing all minerals Experimental: Solution without potassium
7
The 17 Essential Elements = Micro- and Macro- Nutrients
8
Healthy Phosphate-deficient Potassium-deficient Nitrogen-deficient
The most common mineral deficiencies, as seen in maize leaves Healthy Phosphate-deficient Potassium-deficient Figure 37.7 The most common mineral deficiencies, as seen in maize leaves Nitrogen-deficient
9
Deficiency warnings from “smart” plants
Figure 37.8 No phosphorus deficiency Beginning phosphorus deficiency Well-developed phosphorus deficiency
10
The role of soil bacteria in the nitrogen nutrition of plants
Atmosphere N2 N2 Atmosphere Soil Nitrate and nitrogenous organic compounds exported in xylem to shoot system N2 Nitrogen-fixing bacteria Denitrifying bacteria H+ (from soil) NH4+ Soil NH3 (ammonia) NH4+ (ammonium) NO3– (nitrate) Ammonifying bacteria Nitrifying bacteria Figure 37.9 The role of soil bacteria in the nitrogen nutrition of plants Organic material (humus) Root
11
Root nodules on legume plants
Bacteroids within vesicle Nodules Figure Root nodules on legumes Roots 5 µm (a) Pea plant root (b) Bacteroids in a soybean root nodule
12
Development of a soybean root nodule
Rhizobium bacteria Infection thread 1 Chemical signals attract bacteria 2 Bacteroids form Bacteroid 1 Infected root hair Dividing cells in root cortex 2 Development of a soybean root nodule Dividing cells in pericycle Developing root nodule Bacteroid 3 4 Figure Development of a soybean root nodule 3 Nodule forms 4 Nodule develops vascular tissue Nodule vascular tissue Bacteroid
13
(b) Endomycorrhizae Arbuscular mycorrhizae
Epidermis Cortex Mantle (fungal sheath) 100 µm Endodermis Fungal hyphae between cortical cells Mantle - fungal sheath (a) Ectomycorrhizae (colorized SEM) Epidermis Cortex 10 µm Cortical cells Endodermis Figure Mycorrhizae Fungal hyphae Fungal vesicle Casparian strip Root hair Arbuscules Plasma membrane (LM, stained specimen) (b) Endomycorrhizae Arbuscular mycorrhizae
14
In endomycorrhizae, microscopic fungal hyphae extend into the root
Epidermis Cortex 10 µm Cortical cells Endodermis Fungal hyphae Fungal vesicle Casparian strip Root hair Arbuscules Figure 37.12b Mycorrhizae Plasma membrane (LM, stained specimen) Arbuscular mycorrhizae (endomycorrhizae)
15
Unusual nutritional adaptations in plants
Figure Unusual nutritional adaptations in plants Staghorn fern, an epiphyte
16
Unusual nutritional adaptations in plants
Figure Unusual nutritional adaptations in plants Mistletoe, a photosynthetic parasite
17
Unusual nutritional adaptations in plants
Host’s phloem Dodder Haustoria Figure Unusual nutritional adaptations in plants Dodder, a nonphotosynthetic parasite
18
Unusual nutritional adaptations in plants Carnivorous plants
Figure Unusual nutritional adaptations in plants
19
Unusual nutritional adaptations in plants Carnivorous plants
Figure Unusual nutritional adaptations in plants Pitcher plants
20
Unusual nutritional adaptations in plants Carnivorous plants
Figure Unusual nutritional adaptations in plants Sundews
21
Review NO3– (nitrate) N2 N2 (from atmosphere) (to atmosphere)
Nitrogen-fixing bacteria H+ (from soil) Denitrifying bacteria NH4+ NH3 (ammonia) NH4+ (ammonium) NO3– (nitrate) Ammonifying bacteria Nitrifying bacteria Organic material (humus) Root
22
You should now be able to:
Define soil texture and soil composition. Explain why plants cannot extract all of the water in soil. Define cation exchange and describe how plants can stimulate the process. Discuss the problems of topsoil erosion and farm irrigation in arid regions; suggest actions that can help mitigate these problems. Distinguish between and list the macronutrients and micronutrient.s
23
Explain how a nutrient’s role and mobility determine the symptoms of a mineral deficiency.
Summarize the ecological role of each of the following groups of bacteria: ammonifying, denitrifying, nitrogen-fixing, nitrifying. Describe the basis for crop rotation. Distinguish between ectomycorrhizae and arbuscular mycorrhizae. Describe the adaptations for nutrition of parasitic, epiphytic, and carnivorous plants.
Similar presentations
