RNA/DNA ratio (RDR) has been reported to be a feasible biochemical indicator for measuring the growth of numerous aquatic animal species. Nevertheless, its applicability has not been investigated to date in the pearl oyster Pinctada fucata (Gould, 1850). A laboratory experiment was undertaken to determine the relationship between RDR and growth rate in P. fucata postlarvae. The face-centered central composite design was used with three important factors (temperature, algal concentration and stocking density) simultaneously varied to produce a variety of growth rates. Temperature ranged between 18 and 34 °C, algal concentration between 5 and 100 cells μL^―1, stocking density between 0.2 and 2.5 in.. mL^―1. Postlarvae were fed with a 1: 1 mixture of Isochrysis zhanjiangensis and Pavlova viridis over the course of experiment. Results showed that RDR was affected significantly by the first- and second-order effects of and first-order interactions among three factors, but the interactions were negative to the growth of pearl oyster postlarvae. Within the ranges of three factors examined, algal concentration was most important, followed by temperature in influencing the growth of P. fucata postlarvae. RDR was highly positively correlated with specific growth rate (SGR) and absolute growth rate (AGR). Simple linear regression equations of shell height-based growth rates regarding RDR were established, SGR (% d^―1) = ―0.05 + 2.01RDR (R² = 0.98); AGR (μm d^―1) = ―0.02 + 2.82RDR (R² = 0.96). Lack-of-fit test indicated their high adequacy. The models have greater advantages over conventional means of assessing somatic growth, and can be utilized to reliably evaluate recent growth of P. fucata postlarvae under concurrent variations of three factors examined in the present study.

据报道，RNA / DNA比率（RDR）是测量许多水生动物物种生长的可行生化指标。然而，迄今尚未在珍珠贝牡蛎Pinctada fucata（Gould，1850）中研究其适用性。进行了一项实验室实验，以确定褐藻假单胞菌幼虫中RDR与生长速率之间的关系。以面部为中心的中央复合材料设计同时具有三个重要因素（温度，藻类浓度和放养密度），以产生各种增长率。温度范围为18至34°C，藻类浓度为5至100个细胞μL ^-1，放养密度为0.2至2.5 in .. mL^―1。在实验过程中，给幼虫喂食湛江等时线虫和绿色巴甫洛氏菌的1：1混合物。结果表明，RDR受三个因素之间的一阶和二阶效应以及一阶相互作用的显着影响，但这些相互作用对珍珠贝牡蛎幼体的生长不利。在检查的三个因素的范围内，藻类浓度是最重要的，其次是温度，以影响褐藻假单胞菌后幼虫的生长。RDR与比增长率（SGR）和绝对增长率（AGR）高度正相关。）。建立了基于壳高度的有关RDR的简单线性回归方程，SGR（％d ^-1）= 0.05 + 2.01 RDR（R ² = 0.98）；AGR（μmd ^-1）= 0.02 + 2.82 RDR（R ² = 0.96）。缺乏拟合度测试表明它们的充分性。与评估体细胞生长的常规方法相比，该模型具有更大的优势，并且可以用于可靠地评估P的近期生长。本研究中三个因素同时发生变化的情况下，褐毛菜后幼虫。