Heterozygosity, gender, and the growth-defense trade-off in quaking aspen
Heterozygosity, gender, and the growth-defense trade-off in quaking aspen
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DOI：
10.1007/s00442-016-3577-6
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发表时间：
2016-06-01
期刊：
影响因子：
2.7
通讯作者：
Lindroth, Richard L.
中科院分区：
文献类型：
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作者：
Cole, Christopher T.;Stevens, Michael T.;Lindroth, Richard L.
尽管人们普遍认为植物生长受到防御分配、遗传背景（例如近亲繁殖）和性别的影响，但这些因素很少得到集体解决。在颤杨 (Populus tremuloides Michx.) 中，酚苷 (PG) 和缩合单宁 (CT) 占叶子干重的 30%。为了量化这种化学防御的分配成本，我们测量了受控环境和自然环境中雄性和雌性树木的生长、防御化学和个体杂合性（16 个微卫星位点的 H (obs)）。受控环境由 12 个幼体基因组成，它们在一个公共花园中生长了 3 年，并进行复制。自然环境由野生种群中的 51 个成熟基因组成，我们从每个基因中采样了多个分株（树）。 PGs和CTs的浓度呈负相关。 PG 与增长无关，但 CT 生产是主要成本。在野生树木的 CT 水平范围内，生长速度变化了 2.6 倍，因此 CT 浓度增加 10%，生长速度下降 38.5%。 H (obs) 对白杨生长有显着影响：对于野生树木，H (obs) 增加 10% 对应于生长增加 12.5%。在野生树木中，这种 CT 效应仅在雌性树中显着，其中繁殖似乎加剧了防御成本，而 H (obs) 效应仅在雄性中显着。尽管低 H (obs) 树木的生长速度较低，但其较高的 CT 水平可能会提高存活率，这可能是自然白杨种群中反复发现的杂合子缺陷的原因。
Although plant growth is generally recognized to be influenced by allocation to defense, genetic background (e.g., inbreeding), and gender, rarely have those factors been addressed collectively. In quaking aspen (Populus tremuloides Michx.), phenolic glycosides (PGs) and condensed tannins (CTs) constitute up to 30 % of leaf dry weight. To quantify the allocation cost of this chemical defense, we measured growth, defense chemistry, and individual heterozygosity (H (obs) at 16 microsatellite loci) for male and female trees in both controlled and natural environments. The controlled environment consisted of 12 juvenile genets grown for 3 years in a common garden, with replication. The natural environment consisted of 51 mature genets in wild populations, from which we sampled multiple ramets (trees) per genet. Concentrations of PGs and CTs were negatively correlated. PGs were uncorrelated with growth, but CT production represented a major cost. Across the range of CT levels found in wild-grown trees, growth rates varied by 2.6-fold, such that a 10 % increase in CT concentration occurred with a 38.5 % decrease in growth. H (obs) had a marked effect on aspen growth: for wild trees, a 10 % increase in H (obs) corresponded to a 12.5 % increase in growth. In wild trees, this CT effect was significant only in females, in which reproduction seems to exacerbate the cost of defense, while the H (obs) effect was significant only in males. Despite the lower growth rate of low-H (obs) trees, their higher CT levels may improve survival, which could account for the deficit of heterozygotes repeatedly found in natural aspen populations.