Morpho-anatomical characteristics conferring drought tolerance in roots of sugar cane genotypes (Saccharum L., Poaceae)

Abstract

Sugar cane is a major product of Brazilian agriculture, providing about R$ 56 billion of exports per year. Morphological and anatomical analyses enable the identification of plants, whose genotype is still unknown, and increase our knowledge of organs adaptations, such as roots, to different environment conditions. This study aimed to describe the morpho-anatomy of roots of six sugar cane genotypes. Plants were obtained by insertion of stalks in 3L containers filled with coconut fiber substrate. They were held for 7 days in a germination chamber (BOD MA 403) under a 16-h photoperiod with a light intensity of 38 lmol m -2 s -1 and a constant temperature of 35°C. Daily irrigation was performed, keeping the substrate close to saturation. After this period, plants were transferred to a greenhouse and grew under approximately 116 lmol m -2 s -1 of light intensity at 30°C and 80 % relative humidity, during 45 days of daily irrigation. For anatomical characterization, 20 roots from stalks and tillers of five plants per genotype were fixed in FAA 50 % and preserved in alcohol 70 %. For each root, the median region was selected for freehand-sectioning, using a razor blade. The results confirmed that anatomical features might be useful for cultivar identification. RB867515 cultivar showed roots with anatomical features that provide drought resistance, including a reduced number of cortical layers. The roots of SP801816 cultivar had more cortical layers and protoxylem poles in stalks and tillers, indicating a reduced drought resistance.

Leaf Anatomical Adaptation Under Early Drought Stress of Sugarcane Cultivars – KKU-1999-02 and KKU-1999-03

“…Drought stress may decrease vessel diameter (Pinto et al, 2012), which may help avoid cavitation (Zwieniecki & Secchi, 2015). Moreover, reductions in metaxylem diameter and vascular bundle size are normally found in plants under stress conditions, especially drought stress (Da Cruz Maciel et al, 2015) which may result in better resistance to water transportation (Pittermann, 2010). is is in accordance with the results of the present study that the metaxylem diameter of KKU-1999-02 decreased aer drought stress treatment.…”

Effects of Water Regime, Genotype, and Formative Stages on the Agro-Physiological Response of Sugarcane (Saccharum officinarum L.) to Drought

“…Although these varieties have been evaluated under a wide range of environmental conditions, evaluation focused on performance under limiting and excessive moisture conditions has not yet been conducted. The opportunity for varietal improvement for drought tolerance exists as shown by significant differences in varietal response to drought under greenhouse and field conditions, covering both agronomic and physiological parameters [6,[11][12][13][14][15][16]. Understanding the different mechanisms that affect the drought response of a crop will be useful in selecting and identifying genotypes with potential drought tolerance.…”