Oat development in response to temperature

ABSTRACT: Temperature affects plant development therefore phyllochron has been used as a predictor for developmental events to define the time for agricultural managing practices. This study aims to evaluate changes in phyllochron and thermal sum required for flowering by oat genotypes developed at different decades at three temperature regimes; the effect of high temperature on phytomere development; and identify the development stage at the moment of meristem transition to reproductive stage. Three environments were obtained by sowing in the fall, in the spring, and under constant temperature (17oC), always at inductive photoperiod. Despite changes in nominal values small differences were found among genotypes’ phyllochron. Adding specific optimal and maximum temperatures into the growing degree days’ calculation demonstrated phyllochron stability among environments. Plant cycle length and thermal sum correlated with the number of developed phytomeres. UFRGS 078030-2 plants flowered earlier, had a small number of phytomeres, and greater tolerance to elevated temperatures than the other genotypes. More recent genotypes transit to reproductive stage at an earlier Haun stage than older ones.摘要：温度会影响植物生长发育，因此出叶间隔期（phyllochron）常被用作发育事件的预测指标，用以明确农业生产管理作业的实施时机。本研究旨在达成三项研究目标：一是评估不同年代培育的燕麦基因型在三种温度模式下的出叶间隔期与开花所需积温（thermal sum）的变化；二是明确高温对茎节单元（phytomere）发育的影响；三是确定分生组织（meristem）向生殖阶段转变时所处的发育时期。本研究通过秋播、春播以及设置恒温（17℃）三种方式构建三个试验环境，所有处理均处于诱导型光周期（inductive photoperiod）条件下。尽管名义值存在变化，但各基因型的出叶间隔期仅存在小幅差异。将特定最优温度与最高温度纳入生长度日（growing degree days）的计算后，进一步验证了出叶间隔期在各试验环境间的稳定性。植株生育期长度与积温均与已形成的茎节单元数量呈显著相关。相较于其他供试基因型，UFRGS 078030-2植株开花更早、茎节单元数量更少，且对高温的耐受性更强。相较于育成年代较早的基因型，近年育成的基因型会在更早的豪恩发育期（Haun stage）完成向生殖阶段的转变。