Igor Vinícius de Oliveira, Karen Cristina Pires da Costa, Adamir da Rocha Nina Junior, Josiane Celerino de Carvalho, José Francisco de Carvalho Gonçalves
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引用次数: 0
Abstract
Bertholletia excelsa Bonpl. is widely planted in the Amazon and information about thinning effects is poorly documented. Here, we investigate thinning effects on the ecophysiology of B. excelsa plantations. The thinning trial was set up as a randomized complete block design (RCBD) with two treatments (unthinned and thinned to 50% basal area removal). The canopy openness of plots thinned was two times higher than the unthinned treatment (control). B. excelsa under thinning growed three times in relation to trees of control. One week after thinning, we observed increase of 25% photosynthesis (PN), 100% respiration (Rd), 35% stomatal conductance (gs), and 25% transpiration (E). After thinning, we verified reduction of the maximum photochemical efficiency of photosystem II (FV/FM), with subsequent recovery. At the end of 5 months after thinning, the trees on thinned plots achieved values of leaf mass per area (LMA), nitrogen (Na), phosphorus (Pa), and potassium (Ka) about 27% higher than trees of unthinned plots. Thinning did not affect the midday leaf water potential (Ψw). Thinning increased the growth of B. excelsa influenced by photosynthetic performance and regulated by the gs, LMA, leaf Na, and Pa concentrations. Our findings demonstrated that thinning can be recommended for timber production under the dense planting of Brazil nut trees cultivated in degraded Amazonian areas.
Bertholletia excelsa Bonpl.广泛种植于亚马逊地区，但有关疏伐效果的资料却很少。在此，我们研究了疏伐对 B. excelsa 种植园生态生理学的影响。疏伐试验采用随机完全区组设计（RCBD），有两种处理（未疏伐和疏伐至基部面积去除 50%）。疏伐地块的树冠开阔度是未疏伐处理（对照）的两倍。与对照组相比，稀植处理下的 B. excelsa 的生长速度是对照组的三倍。疏伐一周后，我们观察到光合作用（PN）增加了 25%，呼吸作用（Rd）增加了 100%，气孔导度（gs）增加了 35%，蒸腾作用（E）增加了 25%。稀植后，我们发现光系统 II 的最大光化学效率（FV/FM）有所下降，但随后又有所恢复。疏伐后 5 个月，疏伐地块上树木的单位面积叶片质量（LMA）、氮（Na）、磷（Pa）和钾（Ka）值比未疏伐地块上的树木高出约 27%。疏伐并不影响正午叶片水势（Ψw）。疏伐提高了 B. excelsa 的生长，生长受光合作用的影响，并受 gs、LMA、叶片 Na 和 Pa 浓度的调节。我们的研究结果表明，在亚马孙河流域退化地区密植巴西坚果树的情况下，建议进行疏伐以生产木材。
期刊介绍：
The journal does not publish articles in taxonomy, anatomy, systematics and ecology unless they have a physiological approach related to the following sections:
Biochemical Processes: primary and secondary metabolism, and biochemistry;
Photobiology and Photosynthesis Processes;
Cell Biology;
Genes and Development;
Plant Molecular Biology;
Signaling and Response;
Plant Nutrition;
Growth and Differentiation: seed physiology, hormonal physiology and photomorphogenesis;
Post-Harvest Physiology;
Ecophysiology/Crop Physiology and Stress Physiology;
Applied Plant Ecology;
Plant-Microbe and Plant-Insect Interactions;
Instrumentation in Plant Physiology;
Education in Plant Physiology.
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