Costa E Silva Filipe, Shvaleva Alla, Almeida M Helena, Chaves M Manuela, Pereira João S
Instituto Superior de Agronomia, Tapada da Ajuda, Lisbon 1349-017, Portugal.
Funct Plant Biol. 2007 Sep;34(9):793-802. doi: 10.1071/FP07080.
The effect of chilling on growth and plant hydraulic properties in a drought-resistant clone (CN5) and a drought-sensitive clone (ST51) of Eucalyptus globulus Labill. was evaluated. Chilling (10/5°C, day/night) led to a general decrease in growth of both clones and significant reductions in root hydraulic conductivity, rate of photosynthesis and stomatal conductance in comparison to plants grown at control temperature (24/16°C). The drought-resistant CN5 clone maintained higher root growth and lower leaf-to-root-area ratio than the drought-sensitive ST51 clone, in both temperature treatments. Conversely, ST51 exhibited greater carbon allocation to the foliage and higher hydraulic conductance than clone CN5 at both temperatures. Plants of both clones, when acclimated to chilling, maintained a higher hydraulic conductivity than control plants exposed to chilling temperatures without acclimation. Under chilling, the main differences between clones were a higher water status and anthocyanin concentration in CN5 plants, and a stronger inhibition of root growth in ST51 plants. Except for roots, the hypothesis of a lower depression of growth rate in the drought-resistant clone under chilling was not verified. However, higher root growth under low temperatures, as observed in CN5, can be an advantageous trait in Mediterranean-type environments, protecting trees against summer water-stress.
评估了低温对蓝桉抗旱无性系（CN5）和干旱敏感无性系（ST51）生长及植物水力特性的影响。与在对照温度（24/16°C）下生长的植株相比，低温（10/5°C，昼/夜）导致两个无性系的生长普遍下降，根系水力传导率、光合速率和气孔导度显著降低。在两种温度处理下，抗旱的CN5无性系均比干旱敏感的ST51无性系保持更高的根系生长和更低的叶根面积比。相反，在两种温度下，ST51无性系比CN5无性系表现出更多的碳分配到叶片以及更高的水力传导率。两个无性系的植株在适应低温后，其水力传导率均高于未适应低温的对照植株。在低温条件下，无性系之间的主要差异在于，CN5植株具有较高的水分状况和花青素浓度，而ST51植株的根系生长受到更强的抑制。除根系外，抗旱无性系在低温下生长速率降低幅度较小的假设未得到验证。然而，如在CN5中观察到的那样，低温下较高的根系生长在地中海型环境中可能是一个有利性状，可保护树木免受夏季水分胁迫。
