根具有______、______和______的特征，与植物根的______、______有关．
根系在土壤中的分布与其形态和功能有关，也受到环境中水、肥等因素的影响．植物的根系分为直根系和须根系，大多数陆生植物的根在地下分布深而广，形成庞大的根系，比地上的枝叶系统还发达．根在土壤中的分布具有向地性、向水性、向肥性．由于重力作用使根近地的一面生长素浓度高，高浓度生长素对植物根有抑制生长的作用，所以向近地的一面弯曲生长，表现为向下生长即向地性；植物的生长需要水、无机盐等营养物质，水和无机盐是通过根吸收的，因此根还表现为哪水多向哪长的特点，即根的向水性，根向土壤肥力多的地方生长是向肥性．
故答案为：向地性；向水性；向肥性；形态；功能
根据句意选择单词或短语，并用适当形式填空（每词只能使用一次，有两个多余选项）。
小题1:His bad habits of reading in bed _____ his eye-sight． As a result, he had to wear glasses． 小题2: Employees with skills ________ in joint-venture enterprises． 小题3:The performances given by these young people succeeded in _______ a dull play ______． 小题4: At last, my little son _____ to put his whole heart into his studies at school so as to keep up with others． 小题5:In teaching a foreign language, it is important for teachers _____ new teaching methods ___ our teaching process． 小题6:Teaching is an art ______ science． 小题7:Which students ____ the teacher ______when she spoke of the most promising ones? 小题8:On account of his illness, he ___ never ________． 小题9:It is ______ for anyone to laugh at those who are in trouble． 小题10:Many teenagers love to watch a conjurer _______ tricks． |