FROM ECOSYSTEMS TO GENES - THE IMPORTANCE OF SHADE TOLERANCE

Shade tolerance and intolerance are plant properties that are central to ecosystem processes such as succession and regeneration. The recent development and use of accurate and rapid-response field instruments has allowed physiological investigations of tolerance in the field. They show that a major physiological feature of tolerant species is the capacity of shaded leaves to make significant and efficient photosynthetic gains in bright, short-lived sun-flecks, in an otherwise photosynthetically limiting environment. DNA sequences of the chloroplast genome show that genes are extensively conserved between species and provide no evidence of specific genes for shade tolerance in the chloroplast. Nuclear genes also code for chloroplast proteins and probably coordinate the developmental responses of leaves to shade.