Long-distance pine pollen still germinates after meso-scale dispersal

Area of Science:

• Ecology
• Population Genetics
• Forestry

Background:

• Long-distance pollen dispersal is crucial for understanding forest genetic structure and adaptation to climate change.
• Assessing gene flow from genetically modified (GM) pine plantations requires explicit understanding of pollen sources, dispersal, and reception.
• Previous studies have not fully quantified long-distance pollen viability in large-scale forest ecosystems.

Purpose of the Study:

• To measure long-distance pollen germination of Pinus taeda along the North Carolina coastline.
• To test if pine pollen germinates after meso-scale dispersal.
• To evaluate the effect of salt exposure on pollen viability and determine pollen presence at high altitudes before local peak shed.

Main Methods:

• A 160-km transect was established along the North Carolina coast, encompassing mature Pinus taeda plantations and barrier islands.
• Pollen germination rates were measured after dispersal at various distances.
• Experiments included exposure to sodium chloride solutions and high-altitude pollen capture.

Main Results:

• Pinus taeda pollen exhibited germination rates from 2% to 57% at dispersal distances ranging from 3 km to 41 km.
• Exposure to sodium chloride solutions resulted in only a mild reduction in pollen germination.
• Viable pine pollen was detected at an altitude of 610 meters, preceding the local peak pollen shed.

Conclusions:

• Genetically modified pine plantings demonstrate the potential for viable pollen dispersal up to at least 41 km.
• Wind and rainfall significantly influence the genetic structure of forest tree populations through atmospheric systems.
• Understanding long-distance pollen viability is essential for ecological modeling and managing forest genetic resources.