科研之友
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摘要
Arabidopsis noa1 mutant has a small stature and is more resistant to water deficit than wild-type Col-0. To investigate whether the size of noa1 plays a role in drought tolerance, Col-0, noa1 as well as gsnor1-3 and a transgenic line over-expressing a DnaJ domain Hsp40 from soybean (GmHSP40ox), all of which have smaller statures than Col-0, were subjected to drought treatment. Our results showed that the genotypes with smaller statures survived longer than Col-0 under drought conditions when grown in separate containers, which is correlated with the reduced net water losses of plants and the higher water content in the soil during the drought stress treatment. However, when randomly grown in the same containers, the plants of the four genotypes dried out almost at the same time, indicating that the reduced transpirations due to the smaller sizes of the mutant plants might account for the prolonged surviving under drought in separate containers. In the same-container experiment, the accelerated water loss caused by the transpiration of Col-0 plants most likely contributed to the earlier dry-out of the three genotypes with smaller statures because a certain amount of the transpired water through Col-0 could have been used by noa1 gsnor1-3 or GmHSP40ox if grown in separate pots. Interestingly, noa1 had less stomata densities and the stomatal closures of both noa1 and gsnor1-3 were more sensitive to ABA. In addition, noa1 was more resistant to osmotic stress than both Col-0 and gsnor1-3. To our surprise, the water loss rates of detached leaves of both noa1 and gsnor1-3 were greater than that of Col-0, suggesting that the water loss rates of detached leaves may not represent that of in planta leaves. Together, our results suggest that (1) plant sizes of different genotypes must be taken into consideration in evaluating drought trait, and multiple approaches and criteria are needed to ensure the accurate evaluation of drought tolerance; (2) when investigated genotypes have big differences in statures, both the same-container and the separate-container experiments are necessary for screening the resistant or tolerant genotypes; when the investigated genotypes have comparable statures, the separate-container experiment is more relevant; (3) the increased drought tolerance of noa1 is resulted from combined effects of the smaller stature, the increased sensitivity of stomata closure to ABA and the enhanced resistance to osmotic stress; and (4) water loss rate of detached leaves is not a good indicator in evaluating drought tolerance.
- 出版日期2015-7
- 单位浙江师范大学
