Leaf Appearance Base Temperature and Phyllochron for Common Grass and Broadleaf Weed Species

Abstract

Base temperature (Tb) for leaf appearance and the thermal time interval between appearance of successive leaves (phyllochron) were determined for six common weed species from a series of growth chamber experiments. Mean leaf appearance Tbvalues for giant ragweed, velvetleaf, redroot pigweed, large crabgrass, woolly cupgrass, and wild-proso millet were 1.3, 8.0, 8.5, 4.5, 2.2, and 5.1 C, respectively, and mean phyllochron values were 37.2, 34.4, 17.3, 42.2, 65.2, and 34.2 growing degree-days per leaf, respectively. Phyllochron values increased slightly with mean temperature for each weed species. To our knowledge, these are the first reported leaf appearance Tband phyllochron values for giant ragweed, woolly cupgrass, and wild-proso millet. The results confirm leaf appearance Tband phyllochron values reported previously for velvetleaf and redroot pigweed. However, large crabgrass leaf appearance Tband phyllochron values in our study varied somewhat from those reported previously. The results provide information needed for parameterization of plant growth models that predict leaf development based on thermal time.

Initial growth and development of southern sandbur based on thermal units

“…However, it is clear that other environmental variables also influence the development of the species and can potentially complement the mathematical model. The flow and duration of photosynthetically active radiation, the availability of nutrients and water, loss of photosynthetic tissue and, undoubtedly, photoperiod can also alter plant growth and development (Russelle et al, 1984;Gramig & Stoltenberg, 2007).…”

“…In addition, it enables a linear relationship between temperature increase and plant development (Gadioli et al, 2000;Gramig & Stoltenberg, 2007). Thus, mathematical models and simulation routines based on the concept of degree days can be used (Medeiros et al, 2000).…”

Growth and development of honey weed based on days or thermal units

“…For redroot pigweed (Amaranthus retroflexus), a species whose photosynthetic cycle type is C 4 , Gramig & Stoltenberg (2007) registered Tb = 8.5. Base temperatures around 10 o C have been registered for bean plant (Medeiros et al, 2000), corn (Gadioli et al, 2000) and switch grass Panicum virgatum (Sanderson & Wolf, 1995 an experiment conducted with a decreasing photoperiod (January-July/2011).…”

“…The flow and length of the photosynthetically active radiation, the availability of nutrients and water, the loss of photosynthetic tissue and, without a doubt, the photoperiod may also affect the vegetal growth and development (Russelle et al, 1984;Gramig & Stoltenberg, 2007). The thorough analysis of the data enables the assumption that neither days nor thermal units, by means of GD, were adequate to estimate the general phenology of honey weed during all four seasons of the year (Figure 2).…”

Phyllochron and leaf appearance rate in oat

“…The air temperature is the main weather factor that influences plant development (Streck 2002;Gramig and Stoltenberg 2007). Phyllochron represents the accumulated thermal time, in °C day, required for the successive leaves appearance in a culm or stem, having as unit °C day•leaf −1 (Hermes et al 2001;Xue et al 2004).…”