Plant Design Online
New growth
Young leaves are generally light green because they emerge without fully synthesized chlorophyll. The new growth on this yew shrub contrasts with the year-old leaves, which are dark green. Each new branchlet represents a module, adding to the larger modules produced by last year;s growth.
Chlorophyll is expensive for the plant to produce (for one thing it is high in trace elements like nitrogen and magnesium). When the threat of a late frost is still present, a chlorophyll-laden leaf would be an unfortunate sacrifice to cold weather. Plants have evolved to form chlorophyll conservatively in the spring in order to minimize this possibility. The synthesis of chlorophyll requires numerous enzymes as well as energy-rich molecules like ATP. Investing these resources is expensive, and this is another reason that leaves at risk "wait" before producing chlorophyll.
Please join me in my blog “Botany Without Borders: Where Design Meets Science”
botanywithoutborders.blogspot.com/
New growth
Young leaves are generally light green because they emerge without fully synthesized chlorophyll. The new growth on this yew shrub contrasts with the year-old leaves, which are dark green. Each new branchlet represents a module, adding to the larger modules produced by last year;s growth.
Chlorophyll is expensive for the plant to produce (for one thing it is high in trace elements like nitrogen and magnesium). When the threat of a late frost is still present, a chlorophyll-laden leaf would be an unfortunate sacrifice to cold weather. Plants have evolved to form chlorophyll conservatively in the spring in order to minimize this possibility. The synthesis of chlorophyll requires numerous enzymes as well as energy-rich molecules like ATP. Investing these resources is expensive, and this is another reason that leaves at risk "wait" before producing chlorophyll.
Please join me in my blog “Botany Without Borders: Where Design Meets Science”
botanywithoutborders.blogspot.com/