Parameters affecting the early seedling development of four neotropical trees under oxygen deprivation stress.
Some of the parameters that determine flooding resistance-and consequently habitat zonation-were investigated in four neotropical trees (Schizolobium parahyba, Sebastiania commersoniana, Erythrina speciosa and Sesbania virgata). The constitutive parameters of seeds (size, nature and amount of reserves) only partly influenced resistance to flooding, mainly through a high carbohydrate : size ratio. Parameters describing metabolic efficiency under stress conditions were more important. Among them, fermentation capacity and levels of ATP and of total adenylates played a key role. The highest resistance to anoxia was associated with increased availability of free sugars, elevated alcohol dehydrogenase activity and corresponding mRNA levels, more efficient removal of ethanol and lactate, and higher adenylate levels. Finally, as a lethal consequence of energy shortage, free fatty acids were released on a massive scale in the flooding-sensitive species Schizolobium parahyba, whereas lipid hydrolysis did not occur in the most resistant species Sesbania virgata.
Kolb
Rosana Marta
RM
Department of Plant Physiology, IB, State University of Campinas/UNICAMP, Brazil. rkolb@unicamp.br
Rawyler
André
A
Braendle
Roland
R
D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000096:biosynthesis; D000693:Anaerobiosis; D050260:Carbohydrate Metabolism; D004734:Energy Metabolism / Q000502:physiology; D000431:Ethanol / Q000378:metabolism; D019665:Euphorbiaceae / Q000254:growth & development / Q000378:metabolism; D007887:Fabaceae / Q000254:growth & development / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005285:Fermentation / Q000502:physiology; D018525:Germination / Q000502:physiology; D019344:Lactic Acid / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012639:Seeds / Q000254:growth & development* / Q000378:metabolism; D013997:Time Factors; D014197:Trees / Q000254:growth & development* / Q000378:metabolism; D014329:Tropical Climate
D005227:Fatty Acids; D012333:RNA, Messenger; D019344:Lactic Acid; D000431:Ethanol; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D000426:Alcohol Dehydrogenase; D010100:Oxygen