不同养分缺乏对烤烟根系形态及营养生长的影响

为了弄清矿质元素缺乏对烟苗生长的影响,以K326和湘烟四号两个烤烟品种幼苗为材料,在氮、磷、钾、钙、镁、硫、铁缺乏条件下观察烟株的缺素症状,并测定根系形态和植株生物量。结果表明,两个烤烟品种在7种缺素条件下地上部和根系均出现各自特有的症状,其中缺铁症状出现最早,缺硫症状出现最晚。缺氮处理促进K326和湘烟四号烤烟根系生长,其中根系生物量分别比对照增加80.0%和78.1%,然而地上部生物量明显下降。而缺硫处理对两个烤烟品种的根系形态和地上部生物量影响不大。其他缺素处理下,两个品种的根系和地上部生物量明显下降,K326品种的侧根数也显著降低,但是湘烟四号品种仅在缺镁和缺铁处理中降低明显。

Effect of Different Nutrient Deficiencies on Root Morphology and Vegetative Growth in Flue-Cured Tobacco

Two tobacco cultivars K326 and Xiangyan 4 were selected to investigate nutrient deficiency symptoms, root morphology, and biomass under the nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S) and iron (Fe) deficient treatments in order to identify the effects of nutrient deficiencies on tobacco seedling. The results indicated that the shoots and roots of both cultivars appeared specific symptoms under 7 element deficiency treatments. Among them, Fe deficiency resulted in the appearance of the earliest deficient-symptom, but S deficiency resulted in the latest symptom. Compared to the control, N deficiency promoted root growth of K326 and Xiangyan 4, and the root biomass increased by 80.0% and 78.1%, respectively. However, N deficiency decreased shoot biomass of both tobacco cultivars. S deficiency had the least effect on root morphology and plant biomass of two cultivars. Under the other element deficiency treatments, the biomass of shoots and roots decreased remarkably for both cultivars. The lateral root number of K326 also declined rapidly, however, for Xiangyan 4, its lateral root number reduced sharply only under Mg and Fe deficient treatments.