PLANT ECOPHYSIOLOGY

1.      How do plants cope with excess light when it is very cold?

 e.g. avoid the morning sun

Excess light energy can generate toxic oxygen molecules that damage the photosynthetic membranes of the plant, a condition known as photoinhibition. Photosynthesis relies on efficient absorption of sunlight . However in cases of extreme sunlight, plants are forced to absorb light energy in excess of what is needed in photosynthesis. The excess light energy can cause serious damages, such as bleaching in leaves. To protect themselves from damages, plants employ a mechanism wherein the excess light energy is converted to heat which is harmlessly released. The process is called photoprotection.

2.      How do plants cope with soils deficient in phosphorus?

e.g. grow cluster roots

Plants have multiple strategies to cope with phosphorus deficiency such as modifications of root architecture (cluster roots), mycorhiza associations, and exudation of compounds that increase phosphorus availability in the soil. An additional strategy that is only just receiving attention is replacement of phospholipids with non-phosphate containing membrane lipids. This exciting and novel project will determine the role of lipids in tolerance of phosphorus deficiency. Such information can then be used to develop agricultural and forest crops that are more tolerant of phosphorus deficiency.

3.      How do plants cope with excessive salt?

e.g. sequester salt in salt bladders

Secreting Salt From Leaves. Other plant adaptations involve secreting excess salt through the plant's leaves.

4.      How do plants manage to grow in deep shade?

e.g. use light flecks

Most bryophytes are adapted to capture of low light intensities due to their one-cell-thick leaves and lack of well-developed cuticle.  Responses of bryophytes to low light are with increased chlorophylls and antenna pigments, depressed light saturation and compensation points, and deeper green color. Light saturation points are likewise low, although some bryophytes seem able to use bursts of high light intensity and can increase their saturation points when higher levels of CO₂ are available.

5.      What mechanism enable a barley variety cope better with manganese deficiency than other variety?

Manganese is regarded as having the functions of a catalyst; its activities being specially concerned with oxidation and reduction reactions within the plant tissues. Initially pale leaves, whilst later the older leaves show rows of interveinal white streaks near the mid-point of the leaf. The underlying physiological mechanisms are still incompletely understood, despite the fact that numerous studies have been initiated to examine the issue during the last decades. Exudation of MnO2-reducing root exudates. The loss of adaptive mechanisms that optimize photosynthetic performance under varying light conditions or leading to diminished photoprotection may provide a mechanistic cause for a significant fraction of the grain yield reduction that occurs when barley plants are exposed to Mn deficiency.

6.      Why so few plant species in one place?

Plant species in this place  may occur due to changes in climate, weathering of soils, and introduction or extinction of species change the physical and biotic environment. Those plant species that can grow and reproduce under the new conditions or respond evolutionarily so that their physiology provides a better match to this environment will persist.