Fresh matter production by two forms of Oxalis latifolia as influenced by soil and climate

Oxalis latifolia is a widely distributed weed that mainly affects corn fields, orchards, plant nurseries and gardens. Two forms of the weed have been identified: the common form, with fish-tailed leaflets, bulbils growing on stolons and dark pink flowers, and the Cornwall form, with rounder leaflets, sessile bulbils and whitish-pale pink flowers. In this study, the fresh matter production, expressed as the increase of the bulbs’ fresh weight, of both forms was compared during two growing seasons in two locations. The bulbs were grown in pots from spring to autumn, and different aspects of growth were measured at the end of each season. The total fresh matter production, weight of the apical bulb, total weight of the lateral bulbs and number of lateral bulbs differed between the forms, but the mean weight of the lateral bulbs did not. The production of fresh matter was related mainly to the climatic conditions, with both forms of O. latifolia being sensitive to excess rainfall (e.g., > 100 mm) in June and July. The two forms of O. latifolia differed with respect to the fresh matter allocation to the apical or lateral bulbs, suggesting a difference in their growth strategies. The common form developed a light apical bulb and devoted more resources to the lateral bulbs, whereas the Cornwall form developed a heavy apical bulb and many comparatively smaller lateral bulbs. Despite their relative indifference to the soil type, the differences between the two forms suggest that they originated from different climatic regions and that they may differ in their invasive abilities

Poblaciones infestantes de Oxalis latifolia en tres cultivos de Guipúzcoa

Se estudia la distribución de tres poblaciones de Oxalis latifolia, una de huerta, otra de maizal y la tercera de vivero, en cuanto al origen apical o lateral- y al peso de los bulbos; así mismo, se analiza la forma taxonómica common o cornwall- a que pertenecen los bulbos hijos apicales

Identificación de bulbos de las formas Common y Cornwall y de sus bulbos apicales y laterales de Oxalis latifolia kunth.

Se describen los caracteres morfológicos y cromáticos que permiten distinguir las dos formas de Oxalis latifolia, common y cornwall, así como los tipos de bulbos que aparecen en las poblaciones naturales de los campos de cultivo

Biología de Oxalis latifolia: revisión acerca de su origen, ciclo anual, características biológicas más notables y formas taxonómicas

Biología de Oxalis latifolia: revisión acerca de su origen, ciclo anual, características biológicas más notables y formas taxonómicas. En el presente trabajo se describe el origen, ciclo anual de la planta de Oxalis latifolia, comúnmente conocida como trebolillo de huerta o aleluya. Las razones para abordar esta investigación han sido principalmente dos: por un lado, el avance en el conocimiento de esta mala hierba hace necesaria una actualización de toda la información sobre su biología y ecología que, a su vez, abre nuevas posibilidades de control de la misma; y por el otro, su rápida y preocupante dispersión. También se comentan las características más notables de O. latifolia: su pecíolo, carácter superficial, capacidad de rebrote, gran productividad y multiplicación y rejuvenecimiento anual. Estas características convierten a esta planta en una mala hierba difícil de erradicar en huertas, maizales y jardines, por lo que su presencia no es deseada. Finalmente, el presente estudio recopila las diferencias que se han encontrado entre las formas common y cornwall de la mala hierba

Modelling leaf development in Oxalis latifolia

This study was carried to develop functions that could explain the growth of Oxalis latifolia, in both early stages and throughout the season, contributing to the improvement of its cultural control. Bulbs of the Cornwall form of O. latifolia were buried at 1 and 8 cm in March 1999 and 2000. Samples were destructive at fixed times, and at each time the corresponding BBCH scale codes as well as the absolute number of growing and adult leaves were noted. Using the absolute number of adult leaves (transformed to percentages), a Gaussian curve of three parameters that explains the growth during the season (R2 = 0.9355) was developed. The BBCH scale permitted the fit of two regression lines that were accurately adjusted for each burial depth (R2 = 0.9969 and R2 = 0.9930 respectively for 1 and 8 cm). The best moment for an early defoliation in Northern Spain could be calculated with these regression lines, and was found to be the second week of May. In addition, it was observed that a burial depth of 8 cm does not affect the growing pattern of the weed, but it affects the number of leaves they produce, which decreases to less than a half of those produced at 1 cm

Effect of burial on productivity and extinction of Oxalis latifolia Kunth

The effect of burial on productivity and extinction of Oxalis latifolia bulbs has been studied. Linear regression formula showed that complete extinction of bulbs would be possible only at a burial depth of 32 cm. O. latifolia also sacrificed a number of its descendents in order to maintain its mean weight at increasing depth, mainly at depths greater than 28 cm, where a change in productivity distribution was observed. A comparison of these results with field population weights showed that a combination of agro-ecosystem conditions and deep burial would improve control of the weed