GROWTH, TUBER FORMATION AND SPREAD OF CYPERUS ROTUNDUS L. FROM SINGLE TUBERS*

Abstract

Summary. Single tubers of Cyperus rotundus L. were planted at intervals over the year. Plant growth was slow and sprouting of tubers was inhibited at temperatures below 20°C, but tubers overwintered at temperatures above freezing point. In the warm season, plant growth and tuber formation rate closely followed air temperature and tubers were forming within 1 month from planting. No inflorescence appeared during the cool season. In autumn‐planted C. rotundus grown in containers, the ratio of aerial to subterranean weight decreased from 1·1 in December to 0·2–0·4 in summer. The weight of tubers in mid‐summer was about 10 times more than that present in December. Tubers formed at ail times of year and at various locations on plants sprouted readily in laboratory tests (76–100% sprouting). C. rotundus planted in March at wide spacings was grown in field conditions free of other plant competition for 20 months. Within 2 months the plants had spread to 90 cm. At the end of the first and the second summer of growth, the mean area of one plant was 7·6 m2 and 56·7 m2, respectively, and patches had expanded then by 2·8 m and 5·4 m, respectively, from the initial shoot. After 20 months of growth all tubers were present within the 0–40 cm soil depth, 60–70% of them in the 0–20 cm layer. About 30% of the tubers were within 1 m and 60% within 2 m of the plant centre. Under the patch centre there were about 1000 tubers per m2 with 0·3 kg dry weight; in the upper 20 cm more than 3500 tubers weighing 0·9 kg were present per m3 of soil. Croissance, formation de tubercules et propagation de Cyperus rotundus L. issu de tubercules uniques

The effect of the fungus, Balansia cyperi Edg., on growth and reproduction of purple nutsedge, Cyperus rotundus L.

“…Time to sprouting averaged about 9 d in the first experiment which also was consistent with earlier reports of tuber sprouting taking 6-10 d (Hauser, 1962;Horowitz, 1972). In contrast, tubers collected and planted in January 1986 bad lower sprouting rates and those that did sprout took longer compared to tubers collected the previous summer ( Table 2).…”

“…Although Hammerton (1975) found no correlation between time to tuber sprouting and planting dates, his research was carried out in Jamaica, where seasonal variations arc less extreme than those found in Louisiana. Horowitz (1972) also found no correlations but his experiments were carried out in Israel, a temperate-latitude region. In Louisiana, the seasonal diHerences in sprouting were especially pronounced in infected tubers.…”

“…Horowitz (1972) reported that tuber weigbt in outdoor pot culture varied seasonally with temperature and that larger tubers were produced during warm montbs. Hammerton (1975) also suggested that mean temperature were the most important factor influencing tuber size.…”

Evaluation of Crop Seed Powders as Amendments for Purple Nutsedge (Cyperus rotundus) Control Compared to the Traditional Herbicide, Roundup

“…Greater than 95% of purple nutsedge tubers form within 45 cm of the soil surface (Stoller and Sweet, 1987). At temperatures averaging above 20 °C and under the influence of light, purple nutsedge buds sprout from nodes along the ends of the tubers and generate one or two rhizomes which then make their way upward through the soil to produce the basal bulbs (Horowitz, 1972;Groenendael and Habekotte, 1988). …”

“…Mechanical control may even contribute to the translocation of tubers to areas where there previously were none (Rotteveel, 1993). Under favorable environmental conditions and in the absence of interspecies competition, one purple nutsedge plant can generate between 10 million and 30 million tubers per ha in a single growing season (Horowitz, 1972). Tubers can persist in a dormant state within the soil for an average of 3-4 years but have been known to remain viable for as long as 10 years (Schonbeck, 2014).…”