油菜素内酯对毛豆幼苗生长及其抗渍性的影响

试验采用不同浓度油菜素内酯对毛豆幼苗进行叶面喷施处理,测定其在渍水胁迫下对毛豆营养生长和生理特性的影响。结果表明:采用一定浓度的油菜素内酯处理可以促进苗生长、提高根系活力、叶绿素含量、脯氨酸含量和抑制丙二醛增生、降低细胞膜透性,增强了毛豆幼苗对渍水环境的抵抗能力。从叶面喷施后对毛豆的营养指标和生理指标进行综合判断可知:在试验的范围内,以1mL/L油菜素内酯的处理效果为最佳。     

Soybean leaf hydraulic conductance does not acclimate to growth at elevated [CO2] or temperature in growth chambers or in the field

Background and Aims

Leaf hydraulic properties are strongly linked with transpiration and photosynthesis in many species. However, it is not known if gas exchange and hydraulics will have co-ordinated responses to climate change. The objective of this study was to investigate the responses of leaf hydraulic conductance (K_leaf) in Glycine max (soybean) to growth at elevated [CO₂] and increased temperature compared with the responses of leaf gas exchange and leaf water status.

Methods

Two controlled-environment growth chamber experiments were conducted with soybean to measure K_leaf, stomatal conductance (g_s) and photosynthesis (A) during growth at elevated [CO₂] and temperature relative to ambient levels. These results were validated with field experiments on soybean grown under free-air elevated [CO₂] (FACE) and canopy warming.

Key results

In chamber studies, K_leaf did not acclimate to growth at elevated [CO₂], even though stomatal conductance decreased and photosynthesis increased. Growth at elevated temperature also did not affect K_leaf, although g_s and A showed significant but inconsistent decreases. The lack of response of K_leaf to growth at increased [CO₂] and temperature in chamber-grown plants was confirmed with field-grown soybean at a FACE facility.

Conclusions

Leaf hydraulic and leaf gas exchange responses to these two climate change factors were not strongly linked in soybean, although g_s responded to [CO₂] and increased temperature as previously reported. This differential behaviour could lead to an imbalance between hydraulic supply and transpiration demand under extreme environmental conditions likely to become more common as global climate continues to change.     

Aphids decelerate litter nitrogen mineralisation through changes in litter quality

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