The area of individual leaves in oil palm has been conventionally estimated from a regression equation that is based on the size and number of leaflets. The aim of the present study is to verify the accuracy of this equation, which became standard in oil palm research. Therefore, true leaf area, measured with a video camera, was estimated from the product of number of leaflets per leaf (n) with mean length (l) times mid-width (w) of six of the longest leaflets (nlw). The database was assembled, annually for the first 4 years after planting, from 2961 leaves of dura × pisifera testcrosses descending from six distinct pisifera origins. The regression coefficients of the regression lines of nlw plotted against true area did not show a trend with age of the palms or a difference among pisifera origins. The common regression equation fitted through all data of this study accurately estimated true leaf area of the testcrosses and also the areas of 2- to 3.5-year-old dura palms of three distinct origins as well as 18-year-old tenera palms. These outcomes are at odds with the conventional regression equation that overestimates the true leaf areas by about 24%. A more recently-developed variant underestimates true area of the young tenera and dura palms by 28%, while overestimating true area of old tenera palms by 19%. Possible causes for these deviations from true area are discussed. The paper argues that parameters depending on leaf area of previous physiological studies need to be reassessed.

中文翻译：

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用线性回归方程重新评估油棕 (Elaeis guineensis Jacq.) 的叶面积估计

传统上，油棕中单片叶子的面积是根据基于小叶大小和数量的回归方程来估计的。本研究的目的是验证该方程的准确性，该方程已成为油棕研究的标准。因此，用摄像机测量的真叶面积是根据每片叶子的小叶数的乘积估算的（n) 与平均长度 (l) 乘以中宽 (w) 六张最长的传单 (nlw）。该数据库在种植后的前 4 年每年从 2961 片硬脑膜×梨花来自六个不同的测试交叉梨花起源。回归线的回归系数nlw与真实面积作图并没有显示出手掌年龄的趋势或手掌之间的差异梨花起源。通过本研究所有数据拟合的通用回归方程准确估计了测试杂交的真叶面积以及 2 至 3.5 岁的面积硬脑膜三个不同起源的手掌以及 18 岁特内拉手掌。这些结果与高估真实叶面积约 24% 的传统回归方程不一致。最近开发的变体低估了年轻人的真实区域特内拉和硬脑膜手掌减少了 28%，同时高估了老年人的真实面积特内拉手掌减少 19%。讨论了这些偏离真实面积的可能原因。该论文认为，需要重新评估取决于先前生理研究的叶面积的参数。