Rhizome Dry Weight Research Articles

SPATIAL GROWTH OF CYNODON DACTYLON (L.) PERS.*

Summary. Small sprigs of Cynodon dactylon (L.) Pers., were planted and grown without competition from weeds and crops for 2 1/2 years. The plant spread by means of above‐ground creeping stolons and subterranean rhizomes which could also emerge as aerial shoots, producing in their turn new stolons and rhizomes. Initially there was linear extension of stolons and rhizomes, following which gaps in the sod were filled by stolon branching and new shoots. There was no preferential direction of stolon elongation and established sods developed an approximately circular shape and expanded concentrically. The rate of increase in sod area was similar in both years of observation but radial extension was smaller in the second year than in young plants.The mean sod area was 25 m2 after 2½ years of growth, and mean monthly area increment was 0·9 m2. Growth almost stopped in the cold season and exceeded 2 m2 per month in the summer. The plants had extended up to 3·9 m from the plant centre after 2 1/2 years. The number of flowering culms per sod, produced only in the warm season, was directly proportional to sod area; seeds were infertile in the Newe Ya'ar area.After 2½ years of growth about 70% of the rhizome dry weight was present in the upper 20 cm of soil. Few rhizomes penetrated deeper than 40 cm. More than 60% of the rhizomes were present within 1 m radius of the plant centre and 90% were present within 2 m radius. Croissance spatiale de Cynodon dactylon (L.) Pers.

EFFECTS OF LIGHT INTENSITY, PHOTOPERIOD AND NITROGEN ON THE GROWTH OF SEEDLINGS OF AGROPYRON REPENS (L.) BEAUV. AND AGROSTIS GIGANTEA ROTH

Summary. Seeding of Agropyron repens (L.) Beauv. und Agrostis gigantea Roth were grown in two photoperiods and with amounts of nitrogen. On two occasions plants transferred between photoperiods.The early growth of the seedlings was increased most by increasing the light intensity, but later nitrogen had the greatest effect. In short photoperiods, plants of both species were decumbent and had many more shoots than in long photoperiods. At the end of the experiment, plants of both species responded more to nitrogen in bright than in dim light, and the dry weight of Agropyron was increased more than that of Agrostis by increased photoperiod and nitrogen. Agropyron initiated rhizomes sooner than Agrostis; it had fewer rhizomes but they were longer and thicker and weighed more. Brighter light, longer photoperiod and nitrogen all increased rhizome weight. Photoperiod did this mainly by producing more rhizomes, light by increasing thickness or density, and nitrogen by both. The effects of photoperiod and nitrogen on the rhizome dry weight of Agropyron, but not of Agrostis, were additive.Transferring plants from short to long photoperiods or from long to short, respectively increased or decreased total growth, but had an opposite effect on the rhizomes.

Effect of irrigation intervals on growth and chemical composition of some Curcuma spp. plants

Abstract. Mohamed MA, Wahba HE, Ibrahim ME, Yousef AA. 2014. Effect of irrigation intervals on growth and chemical composition of some Curcuma spp. plants. Nusantara Bioscience 6: 140-145. The Influence of irrigation intervals on the growth, yield of rhizomes and chemical composition of both Curcuma aromatica and Curcuma domestica plants was investigated. Three irrigation treatments were used in this experiment. The first treatment was irrigated every one week. The second and third treatments were irrigated every two and three weeks. The long irrigation intervals significantly reduced growth parameters and chemical composition. Growth parameters, i.e. plant height, number of leaves, width of the leaf, fresh and dry weight of rhizomes, as well as chemical composition, i.e. total carbohydrate, volatile oil and curcumin in dry rhizomes increased when the plants irrigated every week compared to irrigation treatments every two or three weeks. Also, C. aromatica gave the higher values of growth parameter and chemical composition compared to C. domestica under all irrigation treatments.

EVALUATION OF HERBICIDES FOR THE CONTROL OF COUCHGRASS, AGROPYRON REPENS (L.) BEAUV.

Summary. Two techniques for the comparative evaluation for the control of couchgrass (Agropyron repens (L.) Beauv.) were tested in 1960, and it was concluded that the more practicable was the one in which known lengths (96 in.) of couchgrass rhizome fragments were planted in a plot of 10 × 2 ft. The rhizomes were allowed to grow and herbicides were applied when the shoots were 6–9 in. high. Two to 3 months later the rhizomes were carefully dug up, weighed, measured and dried. Dry weight of rhizomes was used as a measure of the quantity of couchgrass present. Four trials of spring applications, and two of autumn applications are reported.Of the commercially available herbicides, amitrole‐T, TCA and dalapon were effective in that order, and presented no insuperable problems of persistence in the soil. Fenac and atrazine showed little promise. Spring applications of herbicides were considerably more effective than autumn treatments.Essai d'herbicides pour la lutte contre Agropyron repens