Sex-related differences in morphological, physiological, and ultrastructural responses of Populus cathayana to chilling

Abstract

Low temperature is one of the abiotic factors limiting plant growth and productivity. Yet, knowledge about sex-related responses to low temperature is very limited. In our study, the effects of low, non-freezing temperature on morphological, physiological, and ultrastructural traits of leaves in Populus cathayana Rehd. males and females were investigated. The results showed that 4 °C temperature caused a chilling stress, and females suffered from greater negative effects than did males. At the early growth stage of development, chilling (4 °C) significantly inhibited plant growth, decreased net photosynthesis rate (Pn), stomatal conductance (gs), transpiration (E), and chlorophyll pigments (Chl), and increased intercellular CO2 concentration (Ci), chlorophyll a/b (Chl a/b), proline, soluble sugar and H2O2 contents, and ascorbate peroxidase (APX) activity in both sexes, whereas peroxidase (POD) and glutathione reductase (GR) activities decreased and thiobarbituric acid reactive substance (TBARS) content increased only in females. Chilling stress also caused chloroplast changes and an accumulation of numerous plastoglobules and small vesicles in both sexes. However, disintegrated chloroplasts and numerous tilted grana stacks were only found in chilling-stressed females. Under chilling stress, males showed higher Chl and soluble sugar contents, and higher superoxide dismutase (SOD), POD, and GR activities than did females. In addition, males exhibited a better chloroplast structure and more intact plasma membranes than did females under chilling stress. These results suggest that sexually different responses to chilling are significant and males possess a better self-protection mechanism than do females in P. cathayana.

Identifying Differentially Expressed Genes Associated with Tolerance against Low Temperature Stress in Brassica napus through Transcriptome Analysis

“…Peroxidases are a kind of antioxidant enzymes, which can remove ROS in plant cell (Breusegem et al, 1999). Previous studies mainly focused on SOD, POD and CAT activities, however, due to the material properties and the difference of stress duration and intensity, changes in antioxidant enzymes under low temperature stress were not so regular (Gechev et al, 2003;Zhang et al, 2011;Li et al, 2013). In our experiment, the resistant variety initiated osmotic regulation system firstly and then triggered the antioxidant enzyme system when exposed to low temperature stress for long duration.…”

Populus cathayana males exhibit more efficient protective mechanisms than females under drought stress

“…As the different reproduction costs, males and females have evolved different adaptive strategies to environmental stresses (Dawson and Bliss, 1989;Dawson and Ehleringer, 1993). Our previous studies have shown that there are different tolerance and sensitivity in male and female poplars to nitrogen deposition, photoperiod, heavy metals, sanity, chilling and rust disease (Zhao et al, 2009(Zhao et al, , 2011Chen et al, 2010a,b;Zhang et al, 2010aZhang et al, , 2011. In these studies, we found a common phenomenon that male poplars showed higher antioxidant enzyme activities than females under the above stresses.…”

Significance of mesophyll conductance for photosynthetic capacity and water-use efficiency in response to alkaline stress in Populus cathayana seedlings

“…Meanwhile, soil salinization and alkalization frequently co-occur in nature. Although ecophysiological response to environmental change in P. cathayana has been widely measured (Chen et al 2010, Xu et al 2010, Zhang et al 2011, no measurements of g m for P. cathayana have been conducted to our knowledge under alkaline stress. In the present investigation, photosynthesis, g m , PNUE, as well as δ 13 C of P. cathayana were assessed under alkaline stress.…”