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三、主要生态条件对幼虫培养的影响 1.温度各种双壳类的卵与幼虫的发育,各有不同的适溫范围。在适溫以上时,出現畸形发育或很快死亡。在适溫以下时,往往并不立即死亡,而在很长时間內停止进一步发育。在适溫范围以內,最适溫靠近上限,在下限至最适温之間,即使相差几度,发育的速度也有显著的增加。而且在发育的初期,对溫度的适应范围較窄,随着发育过程的进行,适应范围愈来愈广。例如,据Loosanoff(1951)报导,射利帘蛤(Mercenaria mercenarin)在18—30℃范围內可从卵培养到变态,在15℃或33℃下則不能使受精卵发育成正常的直线絞合期幼虫。在上述溫度范围內,越靠近高溫,幼虫生长和变态越快。其他条件相同时,在30℃下幼虫受精后过7—14天完成变态,在18℃下則需16—
Third, the main ecological conditions on the larval culture impact 1. The temperature of a variety of bivalve eggs and larvae development, each have different suitable temperature range. Above the proper temperature, deformities develop or die quickly. Below the proper temperature, they often do not die immediately, but stop further development for a long time. Within the appropriate temperature range, the optimum temperature close to the upper limit, between the lower limit to the optimum temperature, even if the difference of a few degrees, the development of a significant increase in speed. And in the early stages of development, the adaptation range of temperature is narrower, and as the development process progresses, the adaptation range becomes wider and wider. For example, according to Loosanoff (1951), Mercenaria mercenarin can be cultured from egg to metamorphosis at 18-30 ° C and can not develop into normal straight stranded at 15 ° C or 33 ° C Period larvae. In the above temperature range, the closer to high temperature, the faster the growth and metamorphosis of larvae. Other conditions are the same, the larvae are fertilized at 30 ° C for 7-14 days to complete the metamorphosis, and at 18 ° C, 16-