GROWTH ANALYSIS OF HYBRID Eucalyptus urograndis (E. grandis x E. urophylla) IN RESPONSE TO SIMULATED DRIFT OF AUXINIC HERBICIDES

ABSTRACT The aim of this study was to evaluate growth rates of E. urograndis under application of triclopyr and fluroxipyr+triclopyr herbicides. Was used a randomized block design with four replications in a factorial design (3x2x5), corresponding to herbicides (triclopyr and fluroxipyr+triclopyr), both with two doses (0.75 and 1.5% concentrations of 480 g and L-1 for triclopyr and 80+240 g and L-1 for fluroxipyr+triclopyr), plus one control (plants that did not receive herbicide application) and five evaluation dates at 15, 30, 45, 60 and 75 days after application (DAA). At 45 days after seedlings transplant, applications were performed with pressurized carbon dioxide backpack sprayer, equipped with beak tip (XR 110.02) with spray volume of 200 L ha-1 and constant pressure of 35 kgf/cm2. Were evaluated: leaf area (LA), specific leaf area (SLA), leaf area ratio (LAR), leaf weight ratio (LWR), absolute growth ratio (AGR), relative growth ratio (RGR) and net assimilatory ratio (NAR). The drift of triclopyr and fluroxipyr + triclopyr herbicide in the hybrid E. urograndis affect plant development in the beginning of the establishment. At 75 days after simulation drift of herbicides the plants showed characteristics of the symptoms of intoxication. It’s necessary to perform studies after 75 DAA to verify the complete recovery of the intoxication symptoms of E. urograndis hybrid plants resulting from the herbicide drift in the present study.

摘要：本研究旨在评估尾巨桉（E. urograndis）在施用三氯吡氧乙酸（triclopyr）与氟氯吡氧乙酸+三氯吡氧乙酸（fluroxipyr+triclopyr）除草剂条件下的生长速率。实验采用随机区组设计，设置4次重复，采用3×2×5因子设计：其一为除草剂类型，包含三氯吡氧乙酸、氟氯吡氧乙酸+三氯吡氧乙酸两个水平，另设不喷施除草剂的对照组，共3个处理水平；其二为施用剂量，设置0.75%、1.5%两个浓度梯度——三氯吡氧乙酸的对应制剂浓度为480 g·L⁻¹，氟氯吡氧乙酸+三氯吡氧乙酸的对应制剂浓度为80+240 g·L⁻¹；其三为5个测定时间点，分别为施药后15、30、45、60、75天（DAA，施药后天数）。于幼苗移栽后45天开展喷施作业，使用配备XR 110.02型喷嘴的背负式二氧化碳加压喷雾器，喷雾体积为200 L·ha⁻¹，恒定压力为35 kgf/cm²。本研究测定的指标包括：叶面积（LA）、比叶面积（SLA）、叶面积比（LAR）、叶重比（LWR）、绝对生长速率（AGR）、相对生长速率（RGR）及净同化速率（NAR）。试验结果表明，三氯吡氧乙酸与氟氯吡氧乙酸+三氯吡氧乙酸除草剂的雾滴漂移会对尾巨桉杂交苗的定植初期生长发育造成影响；施药后75天，植株已表现出除草剂药害症状。本研究提示，需在施药后75天以上开展后续研究，以验证本研究中由除草剂雾滴漂移引发的尾巨桉杂交苗药害症状是否可完全恢复。