Effects of nitrogen on the development and growth of the potato plant. 1. Leaf appearance, expanison growth, life spans of leaves and stem branching
1992
Vos, J. | Biemond, H.
Potatoes (Solanum tuberosum L.) were planted in pots in a temperature-controlled glasshouse to collect data on the rate of leaf appearance, leaf expansion, apical lateral branching and active life spans of leaves. The treatments consisted of three rates of nitrogen supply, i.e. the N1 treatment with 2.5 gN per pot and the N2 and N3 treatments with 8 and 16 gN per pot, respectively. The rate of leaf appearance was 0.53 leaves d-1 (one leaf per 28 degrees C d) and was negligibly affected by nitrogen supply. The rate of leaf expansion was related to leaf number and nitrogen supply. The areas of mature leaves increased with leaf number on the main stem to reach a maximum for leaf numbers 12-14, and declined for higher leaf numbers. Leaves on apical lateral branches declined in mature area with increase in leaf number. The expansion rate of leaves was the dominant factor that determined the mature leaf area, irrespective of leaf number and nitrogen treatment. The smallest leaves were observed at the lowest rate of nitrogen supply. Nitrogen promoted apical branching and hence the total number of leaves that appeared on a plant. The proportion of total leaf area contributed by leaves on apical branches increased with time and nitrogen supply. Active life span, i.e. the period of time between leaf appearance and yellowing of the leaf, showed a similar relation to leaf number as mature leaf area, at least in qualitative terms. Leaves of the N3 treatment showed systematically longer life spans than leaves of the N1 and N2 treatment in the order of 3 weeks. The number of main stem leaves was not affected by nitrogen supply.
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