Number Of Main Branches Research Articles

THE EFFECT OF INTRA‐SPECIFIC COMPETITION ON THE DEVELOPMENT OF CHENOPODIUM ALBUM L.

Summary. Plants of Chenopodium album L. were grown at a range of different densities in each of three years. The stem diameter, the number of main branches and the size and number of leaves decreased with increasing density as did weight and leaf area per plant. The dry‐matter yield per unit area increased with density up to 576 plants/m2 in two of the three trial years. The proportion of the seed yield relative to the total yield was higher in the leas dense than in the dense stands, or was almost constant. Density did not affect the seed yield per unit area, but seed yield per plant fell as density increased. Maximum seed production was 41 900 per plant and the mean seed yield over the three years was 8300 seeds per plant. The percentages of nitrogen, phosphorus, potassium and calcium were highest when the plants were at an early stage of development. The proportions of these elements in the dry‐matter yield decreased with increasing age of the plants. The density of the stand did not affect the percentages of elements but the total amounts per plot were greatest at the flowering stage and in the denser stands.

Effects of shading on inflorescence size and development in temperate perennial grasses

SUMMARYSingle plants of S24 perennial ryegrass (Lolium perenne L.) and S215 meadow fescue (Festuca pratensis Huds.) were transferred between, or exposed continuously to, contrasting light intensities obtained by decreasing the natural light in a glasshouse with Tygan shades. Inflorescence development in main shoots was studied by dissections of shoot apices, and by counts of branches and florets when ears emerged. Apical growth was slower, and spikelet initiation and inflorescence development were delayed or inhibited, in decreased light intensities. The number of main branches in the ear depended on the rate of apical growth before and after spikelet initiation, and on the time of spikelet initiation. In meadow fescue these processes were influenced by light intensity. Floret numbers per inflorescence branch were generally decreased by decreased light intensity. Most of the effects of light intensity on inflorescence development were smaller in ryegrass than in meadow fescue.