Main conclusionThe qPCR assay developed to differentiate haploid and diploid maize leaf samples was unsuccessful due to DNA content difference. Haploid cells are packed more closely together with less cellular expansion.AbstractIncreased ploidy content (> 2 N) directly correlates with increased cell size in plants, but few studies have examined cell morphology in plants with reduced ploidy (i.e., haploids). To pioneer a scalable new ploidy test, we compared DNA content and cellular morphology of haploid and diploid maize leaves. The amount of genomic DNA recovered from standardized leaf-punch samples was equivalent between these two ploidy types, while both epidermal and mesophyll cell types were smaller in haploid plants. Pavement cells had a substantially smaller size than mesophyll cells, and this effect was more pronounced in the abaxial epidermis. Interveinal distance and guard cell size were significantly reduced in haploids, but the cell percentage comprising stomata did not change. These results confirm the direct correlation between ploidy content and cell size in plants, and suggest that reduced cell expansion predominantly explains DNA content equivalence between haploid and diploid samples, confounding efforts to develop a haploid detection method using DNA content.

中文翻译：

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单倍体和二倍体玉米叶片中 DNA 含量的等效性

主要结论 由于 DNA 含量不同，开发用于区分单倍体和二倍体玉米叶片样品的 qPCR 检测方法不成功。单倍体细胞更紧密地堆积在一起，细胞扩增更少。摘要增加的倍性含量（> 2 N）与植物中细胞大小的增加直接相关，但很少有研究检查植物中倍性减少（即单倍体）的细胞形态。为了开创可扩展的新倍性测试，我们比较了单倍体和二倍体玉米叶片的 DNA 含量和细胞形态。从标准化的打孔样本中回收的基因组 DNA 量在这两种倍性类型之间是相等的，而在单倍体植物中表皮和叶肉细胞类型都较小。路面细胞的尺寸比叶肉细胞小得多，并且这种效果在背轴表皮中更为明显。单倍体的静脉间距和保卫细胞大小显着降低，但包含气孔的细胞百分比没有变化。这些结果证实了植物中倍性含量与细胞大小之间的直接相关性，并表明细胞扩增减少主要解释了单倍体和二倍体样品之间的 DNA 含量等价性，从而混淆了使用 DNA 含量开发单倍体检测方法的努力。