Gaseous Exchanges and Formation of Aerenchyma in Eucalyptus Clones Submitted to Hypoxia and High Manganese Content  

作　　者：Fellip Januário Pinheiro Lacerda Ivo Ribeiro da Silva Sarah Vieira Novais Edgar Augusto Toledo Picoli Fernando Palha Leite Roberto Ferreira Novais 

机构地区：[1]Vicosa Federal University [2]Sao Paulo Univeristy-ESALQ, Soil Science [3]Celulose Nipo Brasileira S/A

出　　处：《Probe-Soil Science》2019年第1期1-12,共12页探索-土壤科学

摘　　要：In lowlands of Vale do Rio Doce regions it is observed the occurrence of Eucalyptus shoot blight from Vale do Rio Doce (ESBVRD). This anomaly has been observed in regions with a high incidence of rainfall and soils conditions that predispose flooding (hypoxia) and, consequently, Mn available excess. The objective of this work was to evaluate nutritional, physiological and morphological changes possibly involved in the differential tolerance of eucalyptus clones to ESBVRD, under hypoxia conditions and Mn excess. To this end, an experiment was carried out in nutrient solution, in a growth chamber. Two clones of eucalyptus, a sensitive (1213) and a tolerant (2719), were submitted to four O2 concentrations (1;4;6 and 8 mg L^-1), at the presence of 30 mg L^-1 of Mn, concentration considered excessive or toxic. The lengths of the root system and shoots were measured, as well as photosynthesis, stomatal conductance, transpiration and CO2 internal concentration. Also, roots samples were taken near the apex for anatomical analyzes. At the end of the experiment (21 days), the plants were harvested and separated into old and new leaves, stem and root. Afterwards, the levels of Mn in the tissues were determined. The hypoxia condition limited the total dry matter, similar to both clones, although the root growth was the most sensitive indicator of stress condition caused by hypoxia, with more marked effect in the sensitive clone. The tolerant clone replied more clearly to the increase of O2 availability (lower hypoxia), with the increased metabolism due to the greater stomatal conductance, photosynthetic rate, transpiration and CO2 internal concentration, comparing to the sensitive clone. Hypoxia condition caused the most intense formation of aerenchyma in the sensitive clone’s root system, even though the arenchyma formation was also observed in the tolerant clone. Mn excess did not imply in great responses.

关 键 词：FLOODING PHOTOSYNTHESIS SHOOT Blight of Vale do RIO Doce 

分 类 号：P[天文地球]