תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםUsing transplants for growing pepper (Capsicum annuum L.) is widespread, but little is known about seedling response to transient N and P supply during tbe nursery growth stage. The objective of this work was to study the effect of steady and alternating N and P concentrations in solution culture on pepper seedling development, dry-matter production rate, and N and P uptake rates, to allow better control of production by transplants. Seedlings were grown in trays of pyramidal cells, packed with vermiculite and floated on well-aerated nutrient solutions of high (6 mM) or low (1 mM) N and high (0.25 mM) or low (0.01 or 0.03 mM) P. Dry-matter accumulation in seedling tops as a function of time conformed in all treatments to a first-order exponential equation. The growth rate constant was significantly higher in the high than in the low N or P concentrations. Root growth rate was less affected by the N and P solution concentration than was the top growth rate. Five-day-long alternations of solution concentration from high to low and from low to high N and P significantly changed dry-matter production rate and nutrient content in plants. Growth and uptake rates regained their original values when seedlings were re-exposed for 5 d to the original solutions. The rapid changes in growth rate were attributed to rapid variations in the flux of N and P uptake in response to changes in solution concentrations, which affected N and P concentration in plant organs. Varying N and P concentrations in tops affected drymatter production rate, whereas variations in N and P concentrations in roots influenced the flux of uptake of P and N, respectively.
Using transplants for growing pepper (Capsicum annuum L.) is widespread, but little is known about seedling response to transient N and P supply during tbe nursery growth stage. The objective of this work was to study the effect of steady and alternating N and P concentrations in solution culture on pepper seedling development, dry-matter production rate, and N and P uptake rates, to allow better control of production by transplants. Seedlings were grown in trays of pyramidal cells, packed with vermiculite and floated on well-aerated nutrient solutions of high (6 mM) or low (1 mM) N and high (0.25 mM) or low (0.01 or 0.03 mM) P. Dry-matter accumulation in seedling tops as a function of time conformed in all treatments to a first-order exponential equation. The growth rate constant was significantly higher in the high than in the low N or P concentrations. Root growth rate was less affected by the N and P solution concentration than was the top growth rate. Five-day-long alternations of solution concentration from high to low and from low to high N and P significantly changed dry-matter production rate and nutrient content in plants. Growth and uptake rates regained their original values when seedlings were re-exposed for 5 d to the original solutions. The rapid changes in growth rate were attributed to rapid variations in the flux of N and P uptake in response to changes in solution concentrations, which affected N and P concentration in plant organs. Varying N and P concentrations in tops affected drymatter production rate, whereas variations in N and P concentrations in roots influenced the flux of uptake of P and N, respectively.
