[Effects of high CO2 concentration, drought, and their interaction on different stay-green wheat seedlings]. / 高CO2æµ“åº¦ã€å¹²æ—±åŠå ¶äº’ä½œå¯¹ä¸åŒæŒç»¿åž‹å°éº¦å¹¼è‹—çš„å½±å“.

In this study, a pot experiment was carried out to examine the effects of high CO2 concentration, drought and interaction on seedling growth traits, biomass accumulation and physiological characteristics of different stay-green wheat seedlings, with a stay-green wheat variety Yannong 19 and a non stay-green wheat variety Hanxuan 3 as test materials. There were four treatments in the Open Top Chamber with factorial of CO2 concentration (370 µmol·mol-1 vs 550 µmol·mol-1) and drought (45%-55% vs. 75%-85% of field water-holding capacity). Drought significantly inhibited the growth and development of wheat seedlings, while CO2 concentration significantly increased the number of tillers and promoted the growth and development of wheat seedlings. Under drought condition, high CO2 concentration increased the number of tillers of Hanxuan 3 and Yannong 19 by 61.0% and 42.3%, respectively. Under both water conditions, high CO2 concentration significantly increased the biomass of wheat seedlings, and decreased the content of peroxidase and proline in leaves. Under drought condition, high CO2 concentration showed stronger "fertilizer effect". Furthermore, different varieties had different responses to high CO2 concentration, with higher sensitivity of Hanxuan 3 to enhancement of CO2 concentration. Under the scenario of increasing CO2 concentration, the amount of irrigation water applied to a field can be appropriately reduced for efficient use of water resources. Meanwhile, it is necessary to pay attention to the selection of suitable wheat varieties.

[Relationships of wheat leaf stomatal traits with wheat yield and drought-resistance].

Taking the DH population of wheat cultivar Hanxuan10/Lumai14 as test object, and by the methods of correlation analysis and path analysis, this paper studied the relationships of the flag leaf stomatal density (SD), stomatal length and width (SL and SW), stomatal conductance (g(s)), photosynthetic rate (P(n)), and transpiration rate (T(r)) on the 10th and 20th day after anthesis with the yield and the index of drought-resistance under the conditions of drought stress and normal irrigation. Under the two conditions, most of the test leaf traits on the 10th day after anthesis had less correlation with the yield and the index of drought-resistance, whereas the leaf traits on the 20th day after anthesis had significant positive correlations with thousand kernel weight but less correlation with grain number per ear, grain yield per plant, and index of drought-resistance. Path analysis showed that g(s), P(n), and T(r) were the main factors affecting the grain yield per plant (YPP) and the index of drought resistance (IDR), and the effects were stronger both in direct and in indirect ways. The direct and indirect effects of SD, SL, and SW on the YPP and IDR were lesser. Under both drought stress and normal irrigation, and on the 10th and 20th day after anthesis, there were significant correlations between SD and SL, and between SL and SW, g(s), P(n), and Tr, but the correlations of SD and SL with g(s), P(n), and T(r) changed with water condition or growth stage. Therefore, it would be not always a good means to select the leaf stomatal density and size as the targets for breeding to improve the leaf stomatal conductance, photosynthetic rate, and transpiration rate, and further, to promote the yield.

[Drought-resistance of local wheat varieties in Shanxi Province of China: a comprehensive evaluation by using GGE biplot and subordinate function].

Taking 7 local wheat varieties in Shanxi Province of China and two other control varieties as test materials, this paper studied their morphological and physiological traits under normal and water stress field conditions. The drought-resistance coefficient of each index of the traits was calculated. On the basis of principal component analysis, the correlations between the drought-resistance indices and their relationships with the drought-resistance of different varieties were analyzed by GGE biplot, and the drought resistance of the wheat varieties was comprehensively evaluated with the combination of subordinate function and drought resistance index analysis. The main morphological and physiological factors affecting the drought-resistance of the wheat varieties were uppermost internode length, plant height, internode length, leaf area, leaf POD and SOD activities, and leaf relative water content and relative electric conductivity. There existed different degrees of correlation between these indices, and each index had different effects on the drought resistance of the varieties, being the main cause for the different drought resistance of the wheat varieties. Based on the drought-resistance, the test varieties could be classified into three groups, i. e. , drought-resistance group, intermediate group, and sensitive group. Two highly drought-resistance cultivars, Baiheshangtou and Zhuganqing, whose drought-resistance was similar to that of drought-resistant Jinmai 47, could be used as the parent materials for breeding drought-resistance wheat.