Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
Sci Rep. 2016 Nov 22;6:37520. doi: 10.1038/srep37520.
We investigated how pre-dispersal strategies may mitigate the effects of weevil infestation of acorns in a population of Quercus schottkyana, a dominant oak in Asian evergreen broad-leaved forests, and assess if weevil infestation contributes to low seedling recruitment. We counted the number of acorns produced, daily from the end of August to mid-late November for 9 years from 2006-2014. We also recorded the rate of acorn infestation by weevils and acorn germination rates of weekly collections. Annual acorn production was variable, but particularly low in 2011 and 2013. There was no trade-off between acorn production and acorn dry mass. However, acorns produced later in the season were significantly heavier. For most years: (i) the rate of weevil infestation was negatively density dependent (a greater proportion of acorns died with increased acorn density), (ii) the percentage germination of acorns was positively density dependent (proportionately more acorns germinated with increased density), and (iii) as the season progressed, the percentage of infested acorns declined while germination rates increased. Finally, (iv) maximum acorn production, percentage infestation and percentage germination were asynchronous. Although pre-dispersal mortality is important it is unlikely to be the primary factor leading to low recruitment of oak seedlings.
我们研究了在亚洲常绿阔叶林占优势的栓皮栎种群中，种前策略如何减轻象鼻虫对橡子的侵害，并评估象鼻虫的侵害是否导致幼苗的低补充。我们从 2006 年到 2014 年的 9 年中，从 8 月底到 11 月中旬，每天记录橡子的产量。我们还记录了象鼻虫对橡子的侵害率和每周收集的橡子发芽率。年橡子产量是可变的，但 2011 年和 2013 年特别低。橡子的产量和干质量之间没有权衡。然而，在季节后期产生的橡子明显更重。对于大多数年份：（i）象鼻虫的侵害率与密度呈负相关（随着橡子密度的增加，更多的橡子死亡），（ii）橡子的发芽率与密度呈正相关（随着密度的增加，发芽的橡子比例增加），（iii）随着季节的进展，受侵害的橡子比例下降，而发芽率增加。最后，（iv）最大的橡子产量、侵害率和发芽率不同步。尽管种前死亡率很重要，但它不太可能是导致栎树幼苗低补充的主要因素。
