Studies on Conservative and Elastic Characters of Crop Roots

本试验旨在区分作物根系的保守性状（不随环境变化而变化的性状）和弹性性状（随环境变化而变化的性状），获得根系性状引入育种的基本信息。采用离根栽培、水栽培和土栽培三种栽培方法，栽培了6个与同济有关的水稻品种。比较了不同品种幼苗的种子根生长情况。研究结果如下：1。在离根培养条件下，发育完全根性状所需的生长时间为3周（28 ^ C，暗）。2. 各品种均有L型和S型侧根的发生。这一结果证实了这两种侧边都是遗传性状。3. 在断根培养下，发现台中土1号与迪吉乌根的根系性状相似。4. 水培条件下，对茎部的光照影响了根系性状的发育。在光照条件下，植株间根系性状的变异明显减小。5. 在土壤浸没条件下再生长时，种子根性状遗传变异较小，品种间差异不明显。6. 各品种根长性状比根数性状保守。最保守的特征是一阶侧向的密度。通过试验，认为在根系生长条件中加入水分和盐分胁迫，可以扩大各品种基因型的表型可塑性，从而可以对根系的保守性和弹性特性进行评价。

The experiments aimed to make a distinction between conservative (characters which do not vary by environmental variation) and elastic (characters which vary by environmental variation) characters of crop root systems and to acquire the basic information on the introduction of root characters into breding a program. Six rice cultivar related to breed the Tongil were grown under excised root culture, water culture, and soil culture. The seminal root growth of seedlings were compared among cultivar. The results are as follows : 1. The growth duration required to develop fully root characters under excised root culture was three weeks (28 ^ﾟC, dark). 2. The occurrence of both L- and S- type lateral roots was observed in every cultivar under excised root culture. This result confirmed that both types of laterals were hereditary characters. 3. Similarity of root characters between Taicung Native 1 and Dee-Geo Woo-Gen was found under excised root culture. 4. Light radiation to the shoot affected the development of root characters under water culture. Variations of root characters among the plants were reduced significantly when the shoots were exposed to light. 5. When the plants re grown under submerged condition in the soil culture, the hereditary variation of seminal root character was small and difference among the cultivar was not clear. 6. Root length characters were more conservative compared to root number characters in every cultivar. The most conservative character was the density of 1st order laterals. Through experiments, it was considered that by adding the water and salinity stress to the root growth condition, phenotypic plasticity of genotype in each cultivar could be enlarged and evaluation of both conservative and elastic characters of root systems would be possible.