Leaf structure and ultrastructure changes induced by heat and water stress during late reproductive development in field-grown soybean, and their relationship with yield.

CARRERA CONSTANZA S; VEGA CLAUDIA R.C.; ANDRADE FERNANDO H.; FERRUCCI MARÍA SILVIA; ERGO VERÓNICA V.; SOLÍS STELLA M.; GALATI BEATRIZ ; LASCANO RAMIRO H.

Córdoba

Congreso; XXXII Reunión Argentina de Fisiología Vegetal y XV Congreso Latinoamericano de Fisiología Vegetal.; 2018

Sociedad Argentina de Fisiología Vegetal

As a result of climate change, plant production and crop yield are potentially exposed to the devastating effect of the co-occurring terminal drought with high temperatures. The structural and ultrastructural changes induced by heat stress (HS) and water stress (WS) during seed filling (SF) through a morpho-functional perspective and their relationships with physiological-biochemical traits involved in field-grown soybean yield determination were studied. Two soybean cultivars were subjected to the following treatments during SF: HS (>32°C for 6 h per d) during 21 d; WS (20% of available soil water content) during 35 d; and HS and WS combination. A control at ambient temperature and field capacity was also included. HS and WS resulted in significant reduction of yield, but WS prevailed over HS. WS principally reduced leaf area; whereas HS decreased total leaf thickness possible as acclimation strategies related to water conservation and heat dissipation, but also irreversible reducing CO2 assimilation sites. Both stresses damaged outer and inner membranes of chloroplast, causing loss of chlorophyll content and negatively affecting chlorophyll fluorescence. Thus, our multiscale approach provide evidences of alterations in leaf surface, structure and ultrastructure and photosynthesis impairment underling yield limitations under stressful conditions, which is to our knowledge novel.