间伐对塞罕坝华北落叶松干旱抗性的影响

干旱的频发严重影响到华北落叶松的生长。为了分析间伐对塞罕坝地区华北落叶松干旱抗性的影响,在塞罕坝机械林场选取2001年间伐的华北落叶松林分进行树木年轮学取样,采集了25棵树的48个木芯。通过相关分析和t检验分析间伐前后树木生长差异和干旱抗性差异。结果表明,生长季6-7月的温度对树木生长具有负效应,而6-7月降水对树木生长具有正效应。相对于温度和降水,生长季6-7月份的干旱是影响华北落叶松生长的主要限制因子。间伐后树木生长对干旱的敏感性显著低于间伐前(P<0.05),并且间伐后树木对干旱的抗性显著强于间伐前(P<0.05)。我们的研究表明通过间伐可以有效改善塞罕坝地区华北落叶松的生长状况并增强华北落叶松对干旱的抵抗力。

OsSP1基因编辑和过表达对水稻生长和干旱抗性的影响

OsSP1基因是水稻叶绿体定位基因,并且具有明显的干旱响应性。为确定OsSP1基因对水稻生长和干旱胁迫抗性的影响,分别采用CRISPR/Cas9基因编辑技术和基因过表达技术创建了水稻品种中花11 OsSP1基因编辑株系和过表达株系,并通过对靶序列进行片段扩增和测序确定基因编辑植株中OsSP1基因的突变方式,通过hpt序列扩增和潮霉素筛选获得单拷贝插入的纯合过表达植株。表型对比、叶绿素含量测定、过氧化氢测定和干旱抗性分析的结果表明,过表达OsSP1基因对水稻的生长和干旱胁迫抗性均无明显影响,但通过基因编辑引起OsSP1基因突变后,水稻的生长和结实受到了严重影响,在正常生长条件下,T_(0)和T_(1)双等位杂合突变和纯合突变的基因编辑植株均出现矮小、黄化、早衰、不分蘖等生长抑制表型。T_(0)植株结实数很低,T_(1)植株均未抽穗结实,叶片的叶绿素含量也显著或极显著低于野生型和过表达植株,上述结果显示了OsSP1基因在维持水稻正常生长和产量中的关键性作用,为进一步揭示OsSP1基因的作用机制提供了理论和材料基础。

英国冬小麦光周期反应基因Ppd-D1对产量潜力和干旱抗性的影响

小麦是一种长日照作物，较长的日照能减少光周期敏感品种出苗到开花的时间。本试验材料为一对存在Ppd-D1和ppd-D1等位基因差异的近等基因系。Ppd-D1基因能使Mercia平均提早12天开花，使Cappelle-Desprez提早9天开花。在两种遗传背景下，Ppd-D1降低灌溉条件下地上干物质重量0．3～0．9吨，公顷，但是这种降低通过增加收获指数得到了补偿，所以，保持了籽粒产量没有下降。

吴茱萸抗干旱性研究

对吴茱萸耐干旱能力及人工抗旱对吴茱萸生长发育影响进行研究。结果表明:干旱使吴茱萸扦插育苗、幼苗移栽、成年结果树移栽成活率降低,生长发育缓慢,果实大幅度减产;浇水抗旱及采取遮阳措施能明显提高扦插育苗成活率,以每周浇水1次最为理想;浇水抗旱能明显提高幼苗移栽成活率、成年结果树移栽的成活率及果实的产量,使成年结果树产量成倍增长。

大豆Lea5基因过表达提高烟草抗旱和耐盐性的研究

大豆Lea5基因是LEA基因家族成员之一。为分析大豆Lea5基因的功能,构建了大豆Lea5基因植物过表达载体p BI121-Lea5。通过农杆菌介导法转化烟草,获得TL-06、TL-09、TL-17和TL-32等4个转大豆Lea5基因烟草株系。RT-PCR分析表明大豆Lea5基因在4个转基因烟草株系的T2代植株均有不同程度的表达。以转基因TL-09和TL-32株系T2代植株为材料,进行了干旱和盐渍处理,结果表明,2个转大豆Lea5基因烟草株系T2代植株对干旱和盐渍的抗性显著强于野生型烟草,说明大豆Lea5基因可以提高植物抗干旱和盐碱的能力。

4个小麦抗旱相关转录因子基因的表达及其与抗旱生理生化指标的相关性

筛选转录因子基因作为小麦抗旱性鉴定指标,丰富和补充小麦抗旱鉴定体系。以4个抗旱性不同的小麦品种为材料,通过实时荧光定量PCR,检测4个抗旱相关转录因子基因(TaERF1,TaMYB30,TaNAC69,Wabi5)在不同处理时间的表达,同时分析干旱胁迫下4个抗旱生理生化指标的变化,探究4个转录因子基因的表达与抗旱生理生化指标之间的相关性。结果表明,基因TaERF1、TaMYB30、TaNAC69和Wabi5的表达都受干旱胁迫的诱导,且在抗旱性不同的小麦品种中的表达模式存在明显差异;相关性分析表明,TaERF1在各胁迫持续时间点的表达量都与可溶性蛋白和丙二醛(MDA)呈显著或极显著相关,在胁迫处理3h、24h和48h时,TaERF1的表达量与相对含水量(RWC)显著相关,TaMYB30、TaNAC69和Wabi5在一定时段的干旱胁迫后的表达量也分别与可溶性糖、可溶性蛋白、RWC和MDA存在显著相关性。说明转录因子基因TaERF1、TaMYB30、TaNAC69和Wabi5的表达可以作为评估小麦抗旱性的参考指标。

超强辐射抗性微生物:耐辐射异常球菌

耐辐射异常球菌是革兰氏阳性菌,具有独特的细胞结构特征。基因组由两条染色体和两个质粒构成,GC含量较高。与异常球菌属的其他菌种不同,耐辐射异常球菌在整个指数生长期细胞都处于感受态,易于遗传操作。由于具有独特的细胞结构和超强的修复系统,耐辐射异常球菌具有超强电离辐射抗性、UV抗性、氧化抗性、干旱抗性等特征,极具研究和应用价值。

花青苷在果树抗逆中的作用研究进展

花青苷是自然界广泛存在的水溶性色素,分布于果树的根、茎、叶、花和果实等器官中,对果树适应和抵御不良环境具有重要意义。综述了花青苷对果树的光保护机制、低温胁迫和干旱胁迫抗性的生理作用。

石果衣真菌(Endocarpon pusillum)比较转录组分析揭示其抗旱特性

从沙漠地区地衣石果衣中分离得到的地衣型真菌(Endocarpon pusillum)具有极强的抗旱能力.为了研究石果衣真菌的抗旱机制,本研究利用转录组测序和荧光定量的方法分别对纯培养和共生状态的真菌进行分析和比较.比较转录组分析是针对纯培养的石果衣真菌,比较其在正常培养和胁迫培养条件下的2个样品,得到1781个差异表达基因.以抗旱植物和非地衣型真菌的抗旱机制作为参照,一些普遍存在机制中所涉及的基因在石果衣真菌中也是差异表达的.然而不同的是,石果衣真菌的抗旱机制中不涉及有关渗透压调节基因的差异表达,这一特点为揭示石果衣真菌为干旱适应物种提供了证据.此外,石果衣真菌不同于其他生物,还有一系列差异基因被归类于其特有的干旱适应机制.为了确定共生与纯培养状态下的石果衣真菌的抗旱机制是否一致,本研究挑选了23个候选基因,利用荧光定量的方法在脱水地衣体中进行验证.本研究为下一步地衣型真菌的研究提供有价值的数据支持,同时也会有助于抗旱基因的功能研究.

香菇菌糠作栽培基质对番茄幼苗生长的影响

以香菇菌糠为基本栽培基质,将其分别与土壤、煤渣和珍珠岩等混合,研究在干旱胁迫下不同基质配比对番茄幼苗期生长的影响。结果表明:不同处理下番茄幼苗的萎蔫率大小依次为T3<T2<T9<T8<T1<T7<T6<T5<CK<T4;复水后,T2(香茹菌糠∶土壤∶煤渣为4∶6∶6)处理下的番茄幼苗成活率最高,达到94.2%,其次是T3(香茹菌糠∶土壤∶煤渣为5∶5∶5)处理,T4(仅含3份番茄菌糠)处理下的番茄幼苗成活率最低;香菇菌糠混合土壤作为栽培基质在株高、茎粗、叶面积和壮苗指数等方面均显著高于对照,其中以T2处理最好,株高、茎粗、叶面积和壮苗指数分别比对照增加4.34 cm,0.720 cm,102.42 cm2和187.50%;土壤混合基质在抗干旱性、以及幼苗品质特性上都优于其它处理与对照,T2处理效果最好。

Study on Change Laws of Cold Tolerance in Wheat under Drought Stress

In order to study the change laws of cold tolerance in wheat under drought stress, 11 wheat varieties planted in Huang-Huai wheat area and one variety representative in middle-lower Yangtze River wheat area were selected, and the their change laws of cold tolerance under normal moisture condition and drought stress condition. The results showed that under drought condition, the cold tolerance of wheat in various growth stages was remarkably lower than that under nondrought condition, and the decreasing amplitudes were the largest in overwintering stage with an average of 4.91 ℃, the smallest in regreening stage, and in the middle in the jointing stage. Under non-drought condition, the cold tolerance of semi- winter varieties in various growth stages was better than that of spring varieties, there were significant differences between different varieties, and the cold tolerance of all varieties in overwintering stage was improved compared with before winter, and rapidly decreased after overwintering. Semiwinter varieties showed cold tolerance remarkably enhanced in overwintering stage, and the cold tolerance of spring varieties was also improved to a certain degree.

Effects of Drought Stress and Re-watering on Growth and Yield of Different Maize Varieties at Tasseling Stage

[Objective] The aim was to explore the response of different maize vari- eties in Guangxi to drought stress and re-watering at tasseling stage, so as to pro- vide reference for study on drought resistance mechanism, breeding of drought-re- sistant varieties and selection of maize varieties for fall sowing. [Method] At the tasseling stage, total five degrees of drought stress （4, 8, 12, 16 and 20 d） and corresponding re-watering after drought stress were simulated by a tub planting ex- periment in greenhouse for five different maize varieties （Guidan 0810, Dika 008, Zhengda 619, Chenyu 969, Guidan 901）. Normal watering was set as the control. Sampling was carried out on Day 1 after drought stress and on Day 15 after re- watering, and the secondary root number, maximum root length, green leaf number, root dry weight and shoot dry weight were measured. At the harvest time, the ear yield per plant was measured. With yield as the basis, the drought resistance coef- ficient and drought resistance index were calculated. Cluster analysis was conducted for drought resistance coefficient. [Result] The shoot dry weight, root dry weight, secondary root number, maximum root length and green leaf number of maize in the treatment groups decreased compared with those in the control group. The ratio of each index between the treatment and control groups declined with the extension of drought stress. After re-watering, the re-growth amount of each index all de- creased as the stress time prolonged. Post-re-watering over compensation effect oc- curred in none of the indices except the maximum root length, after 4 days of drought stress. Under drought stress, the reductions of all the indices of Guidan 0810, Dika 008 and Zhengda 619 were smaller than those of Chenyu 969 and Guidan 901. After re-watering, the re-growth abilities of Guidan 0810, Dika 008 and Zhengda 619 were stronger than those of Chenyu 969 and Guidan 901. The drought resistance coefficients and drought resistance indexes of Guidan 0810, Dika 008 and Zhengda 619 were all greater than those of Chenyu 969 and Guidan 901. The results of drought resistance coefficient cluster analysis showed that the five maize varieties were classified into two groups： Guidan 0810, Dika 008 and Zheng- da 619 had strong drought resistance, while Guidan 901 and Chenyu 969 had weak drought resistance. [Conclusion] The root and shoot growth of Guidan 0810, Dika 008 and Zhengda 619 was slightly affected by drought stress during the tasseling period, and they restored the growth rapidly after re-watering, thus ensuring high biomass and yield. Therefore, Guidan 0810, Dika 008 and Zhengda 619 can be promoted as drought-resistant autumn maize varieties in Guangxi.

Analysis of Antioxidant Characteristics in Seedling Roots of Sweetpotato(Ipomoea batatas(L.) Lam.) with Different Drought Tolerance under Simulated Drought Stress

[Objective] Jishu 21 with strong drought tolerance and Jizishu 1 with weak drought tolerance were chosen to reveal antioxidant characteristics in seedling roots of sweetpotato with different drought tolerance. [Method] Active oxygen, antioxidant substances and antioxidant enzymes in seedling roots of sweetpotato with different drought tolerance were analyzed by hydroponics with PEG-6000 for simulating drought stress in the experiment. [Result] The results showed that under drought stress, H202 content and formation rate of 02_ in seedling roots of Jizishul were higher than Jishu 21 by 1.9% and 102.6%, respectively, the contents of Vc in seed- ing roots of Jizishu 1 and Jizishu 1 increased by 25.3% and 81.1%, respectively, and the contents of polyphenols increased by 24.8% and 37.6% in the two vari- eties, respectively. The increase amplitudes of Jizishu 1 were higher than Jishu 21 in the above indexes. Antioxidant enzyme activities were higher in seedling roots of Jisl^u 21 and Jizishul under drought stress than normal treatments; and among them, POD activity was the highest, while PPO activity was the lowest in all an- tioxidant enzymes. The increases of SOD, POD, APX and PPO activities in Jishu 21 were twice of those in Jizishul. The bands of SOD3, POD2, CAT1, APX2 and PPO2 changed obviously between the drought treatments of the two varieties. [Con- clusion] In conclusion, stronger drought tolerance in sweetpotato results in lower in- crease amplitudes of H202 content, formation rate of 02- and contents of Vc and polyphenols under drought stress, and the activities of antioxidant enzymes are stronger in seeding roots under drought stress; and the differences in antioxidant enzymes are mainly related to the changes of isoenzymes including SOD3, POD2, CAT1. APX2 and PPO2.

Effect of Soil Drought Stress on Leaf Water Status, Membrane Permeability and Enzymatic Antioxidant System of Maize

A simulation experiment on the responses of maize (Zea mays L.) from the third leaf stage to maturity for different soil water levels (well-watered, moderately stressed, and severely stressed) was conducted by controlling irrigation and using a mobile rain shelter in a neutral loam, meadow soil to determine the effects on leaf water status, membrane permeability and enzymatic antioxidant system for different growth stages. The results indicated that drought stress relied on drought intensity and duration, with more severe drought stress creating more serious effects on maize. Compared with well-watered conditions, during the silking and blister stages moderate stress did not significantly change the relative water content (RWC) and did change significantly the relative conductivity (RC) (P < 0.05) of the leaves; however, severe stress did significantly decrease (P < 0.01) the leaf RWC and increase (P < 0.01) membrane permeability (leaf relative conductivity). Furthermore, under severe drought stress antioxidant enzyme activities declined significantly (P < 0.01) in later stages, namely for superoxide dismutase (SOD) the tasseling and blister stages, for peroxidase (POD) the milk stage, and for catalase (CAT) during the tasseling, blister, and milk stages. Meanwhile, membrane lipid peroxidation (measured as malondialdehyde content) significantly increased (P < 0.01) in all stages.

Physiological Response of Paspalum notatum’s Leaf and Root under Persistent Drought Stress

To investigate the correlation and difference between Paspalum notatum’s leaf and root under drought adversity,this study tested the physiological responses of wild Paspalum notatum’s leaf and root under 0(CK),1,3,5,7,14,21,and 28 d drought stress treatment.These physiological responses include osmotic regulating substance,antioxidant enzyme activity,malonaldehyde content,cell membrane permeability,and chlorophyll content.According to the results,the soluble protein content,proline concentration,malonaldehyde content,cell membrane permeability and CAT activity in Paspalum notatum’s leaf and root tended to increase with the prolongation of drought stress;the soluble sugar content and SOD activity first increased and then decreased;POD dropped gradually;the contents of chlorophyll a,b and total chlorophyll first declined,then mounted,and lastly dropped again.During the early stage of drought stress,SOD and CAT acted as the main antioxidant enzymes in Paspalum notatum’s leaf and root.However,with the aggravation of drought stress the predominant antioxidant enzymes became SOD in the root system whereas CAT and POD in the leaf.It implicates drought has a strong influence on root’s CAT and leaf’s SOD and POD.Leaf is the major organ regulating the osmosis and photosynthesis of Paspalum notatum.The findings can provide a useful theoretical basis for improving Paspalum notatum’s drought tolerance.

Provenance-specific ecophysiological responses to drought in Cunninghamia lanceolata

Aims Cunninghamia lanceolata is one of the most important coniferous species in southern China,but its high sensitivity to drought restricts its expansion.Understanding the intraspecific variation of physiological responses to drought can help us manage this plantation better.Methods We selected 3-year-old seedlings of C.lanceolata,which originated from the low precipitation(LP),middle precipitation(MP)and high precipitation(HP)habitats,respectively.Seedlings were grown under drought stress(20%of soil volumetric water content)for 40 days.The ecophysiological responses and adaptive strategies with different drought tolerance were investigated.Important Findings LP provenance possessed the best tolerance to drought stress,suggesting that considerably increased carbohydrates and nitrogen-containing compounds as osmotic protective materials,which were driven by fast carbon and nitrogen metabolisms.In addition,the highest peroxidase activity could effectively eliminate hydrogen peroxide in drought-stressed LP provenance.The MP provenance reserved a large amount of non-structural carbohydrates,which may act as a certain buffer for encountering drought stress.Importantly,timely closure of stomata to reduce needle transpiration when encountering a water deficiency would help them adapt to long-term drought.MP provenance adopted a conservative water-saving strategy.However,HP provenance regulated root growth(increased root/shoot ratio)and reduced penetration potential to help them absorb water.The different strategies among provenances may be related to the long-term domestication of the geographical environments.Therefore,our results underline the importance of provenance-specific responses to drought stress.It is highly significant to accelerate the selection of drought-resistant germplasms and to cultivate high-yield plantations in the future.