Morphogenetic and structural characteristics of tillers of guinea grass of different age and grazing severities

Abstract

-The objective of this research was to evaluate the effects of tiller age on morphogenic and structural characteristics of guinea grass cv. Mombaca subjected to intermittent stocking and three stubble heights: 30 cm, 50 cm and 50-30 cm. Stubble heights were assigned to experimental units in a completely randomized block design with three replicates.Grazing was performed when canopy intercepted 95% of light incidence. Leaf appearance rate, leaf elongation rate and number of live leaves per tiller were higher in the summer when compared with the winter. Contrarily, stem elongation rate, phyllochron and leaf lifespan were lower in the summer when compared with the winter. During the summer, young tillers had higher leaf appearance and elongation rates when compared with the older ones. Young and mature tillers had the highest values of live leaves per tiller in the summer. There was no difference between summer and winter for the final length of leaf blade between tillers of the same age, except in mature tillers, which had higher final leaf length during the summer. Senescence rate of leaves was higher in young tillers, followed by mature and old tillers. Age of tiller affects morphogenic and structural characteristics of pasture, showing that young tillers have better growth compared with mature and old tillers.

Identification of tiller age categories based on morphogenetic responses of continuously stocked marandu palisade grass fertilised with nitrogen

“…Within nitrogen fertilization rates the pattern of morphogenetic responses measured was the same, justifying the grouping. Previous research with mombaça and tanzânia guinea grasses (CARVALHO et al, 2001) and later corroborated by the results of MONTAGNER et al (2011) andBARBOSA et al (2012) adopted the same groups defined in this experiment, although defining them based on the average dry weight of individual tillers. CARVALHO et al (2001) grouped tillers as young (under two months of age), mature (between two and 4 months of age) and old (more Age categories -1: tillers under 30 days of age; 2: tillers between 30 and 60 days of age; 3: tillers between 60 and 90 days of age; 4: tillers between 90 and 120 days of age; 5: tillers between 120 and 150 days of age; 6: tillers over 150 days of age.…”

“…Experiments have shown that tiller age influences the turnover of leaves on individual tillers (e.g. MONTAGNER et al, 2011;BARBOSA et al, 2012). According to KITAJIMA et al (1997), as plants mature their photosynthetic efficiency decreases, with potential negative effects on rates of leaf appearance and elongation (CARVALHO et al, 2001).…”

Characterization of tillers in deferred Piata palisade grass with different initial heights and nitrogen levels

“…This fact highlights the importance of nitrogen to maintain a younger tiller profile in deferred pasture and thus ensure the continuity of the pasture. There is evidence that the age of tillers influences the morphogenetic and structural characteristics, resulting in progressive loss of vigor with advancing tiller age (Montagner et al, 2011;Paiva et al, 2012).…”

The Tissue Flow in Brachiaria brizantha Pasture Under Intermittent Stocking

“…Thus, pastures in which the handling leads to high leaf appearance rate, in general, present lower final length of leaf blade and also lower LSL (Barbosa et al, 2012;Lemaire et al, 2009;Montagner et al, 2011), but can be modified by the LAI. On this, Menezes et al (2019), suggest that the addition in the LAI could control the light quality that affects the leaf area of forage canopy, causing oscillations in the dynamics of growth.…”