外源丙三醇对干旱胁迫下玉米幼苗抗逆调控作用

以郑单958幼苗为试验材料,设置空白对照(CK)、正常水分条件下1 mmol/L丙三醇(Gly)处理玉米幼苗叶片、20%聚乙二醇(PEG-6000)模拟干旱胁迫(PEG)、20%聚乙二醇模拟干旱胁迫+1 mmol/L丙三醇(PEG+Gly)处理玉米幼苗叶片4个处理展开试验。结果表明,干旱胁迫下外源施用1 mmol/L丙三醇能显著提高叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性;丙二醛(MDA)和过氧化氢(H₂O₂)积累减少;最大光量子效率(F_v/F_m)和光系统Ⅱ潜在活性(F_v/F_o)显著提高,玉米幼苗叶片的净光合速率(P_n)、气孔导度(G_s)和蒸腾速率(T_r)、相对含水率及生长指标均显著提高,胞间CO₂浓度(C_i)降低。因此,外源施用丙三醇能通过降低叶片的氧化损伤和提高细胞保水能力来改善...     

Correlation between Chloroplast Ultrastructure and Chlorophyll Fluorescence Characteristics in the Leaves of Rice (Oryza sativa L.) Grown under Salinity

Abstract

The seedlings of Oryza sativa L. cv. Nipponbare grown by hydroponic culture for 3 wks were treated with 75, 100, 150 and 200 mM NaCl for 14, 14, 6 and 3 days, respectively, and examined for chloroplast ultrastructure in the region where chlorophyll fluorescence had been recorded. NaCl treatment decreased the ratio of variable to maximum chlorophyll fluorescence yield (F_v/F_m) and caused swelling of thylakoids. The swelling of thylakoids was quantified by the percentage of the length of swollen thylakoids to the total length of thylakoids. This value was increased with increasing NaCl concentration. Although F_v/F_m decreased at all concentrations of NaCl, the minimal fluorescence yield F₀ was not increased by the treatment with 75 or 100 mM NaCl. The percentage of the length of swelling was low at 75 and 100 mM NaCl. On the other hand, F₀ increased and the swelling of thylakoids was prominent with 150 and 200 mM NaCl treatment. These results suggest that the decrease in F_v/F_m due to the increase in F₀ under salt stress correlates with the ultrastructural damage. The decrease in F_v/F_m due to the increase in F₀ is expected to be useful as an indicator to evaluate the damage in chloroplasts, especially in thylakoid membranes, under salinity.     

Physio-Biochemical Responses of Oil Palm (Elaeis guineensis Jacq.) Seedlings to Mannitol- and Polyethylene Glycol-Induced Iso-Osmotic Stresses

References

The aim of this investigation was to comparatively examine the physio-biochemical responses of oil palm seedlings to mannitol- and PEG-induced iso-osmotic stresses. The water content of osmotically stressed oil palm seedlings decreased, but the proline content and the electrolyte leakage of the seedlings increased with decreasing water potential (Ψ_w). However, the responses varied with the strength of osmotic stress and type of osmotic agent. Relative electrolyte leakage (REL) was negatively correlated to chlorophyll content in the osmotically stressed leaves. Chlorophyll a (Chl_a), chlorophyll b (Chl_b), total carotenoids (C_x+c) and total chlorophyll (TC) in the seedlings were significantly reduced by osmotic stress, subsequently reducing maximum quantum yield of PSII (F_v/F_m) and photon yield of PSII (Φ_psii), thereby lowering net-photosynthetic rate (P_n) and inhibiting growth. Physio-biochemical parameters, including REL, F_v/F_m, and Φ_psii in oil palm seedlings were reduced more greatly by PEG-induced osmotic stress than by mannitol-induced stress. A deterioration in morphological characters, including leaf chlorosis, leaf burn, and green leaf area reduction were demonstrated in oil palm seedlings under osmotic stress induced by either mannitol or PEG. However, the toxic symptoms in oil palm seedlings under PEG-induced stress were severer than in those under mannitol-induced iso-osmotic stress, especially under severe osmotic stress.     

Characteristics of Gas Exchange and Chlorophyll Fluorescence during Senescence of Flag Leaf in Different Rice (Oryza sativa L.) Cultivars Grown under Nitrogen-Deficient Condition

Abstract

Effects of nitrogen (N) deficiency on photosynthetic gas exchange and photosystem II (PSII) photochemistry of flag leaves during grain-filling stage were investigated in six rice cultivars, Kasalath (a conventional indica), IR36 (an improved indica), Shirobeniya (a conventional japonica), Nipponbare (an improved japonica), Akenohoshi (an improved japonica-indica intermediate type) and BSI429 (an improved tropical japonica, a new plant type line) grown hydroponically in N-sufficient (NS) and N-deficient (ND) solution. From 3 to 24 days after heading (DAH), net photosynthetic rate (P_n), maximum quantum yield of photosystem II (PSII) (F_v/F_m), quantum yield of PSII electron transport ( Φ_psii), and contents of chlorophyll (Chl) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the flag leaves decreased, particularly under the ND condition in all six cultivars. A substantial difference was observed among the ND plants for the sustainability index (SI, the ratio of the value at 24 DAH to that at 3 DAH) of P_n, F_v/F_m, Φ_psii, Chl content and Rubisco content; SIs of those parameters of Akenohoshi, BSI429, Nipponbare and Shirobeniya were higher than those of IR36 and Kasalath. The SI of P_n showed significant positive correlations with those of F_v/F_m, Φ_psii, and the contents of Chl and Rubisco under the ND condition. It was concluded that the sustainability of photosynthesis in the flag leaves was mainly due to those of PSII photochemistry and electron transport, which was associated with the maintenance of Chl and Rubisco under the ND condition.     

Genetic analysis of early-maturing maize (Zea Mays L.) inbred lines under stress and nonstress conditions

Early-maturing maize (Zea Mays L.) germplasm developed from diverse sources has the potential for use in developing maize hybrids suitable for increasing maize production in the dry ecologies of eastern Africa. A diallel study was conducted to estimate general combining ability (GCA) of 12 early-maturing maize inbred lines, identify potential single-cross hybrids for use as parents, assess genetic diversity among the inbred lines, and relate genetic distance to specific combining ability (SCA) and hybrid performance. Sixty-six F₁ diallel hybrids were evaluated under optimal and drought stress conditions at four locations in Kenya and Uganda. The parental inbred lines were genotyped using 94 single nucleotide polymorphism (SNP) markers. Additive gene action was more important than nonadditive gene action for inheritance of grain yield (GY) under optimal conditions. However, nonadditive gene effects were more important in the inheritance of GY under drought and across all environments. Inbred lines CKL0722, VL058014, and CZL0724 were among the best with positive GCA effects for GY across both optimal and drought stress conditions. The correlation between SCA and both genetic distance and F₁ GY was significant under both drought stress and across all environments. Inbred lines with desirable GCA effects for GY and other agronomic traits and hybrids with good performance under both optimal and drought stress conditions are potential parents for development of various types of high-yielding, stress-tolerant, and early-maturing hybrids.     

Photosynthetic Recovery of a Perennial Grass Leymus chinensis after Different Periods of Soil Drought

Abstract

The effects of rewatering after different periods of soil drought stress on the photosynthetic capacity of Leymus chinensis in pots were investigated. The plants were subjected to short-term (10-d), moderate-term (20-day) and long-term (30-d) drought each followed by rewatering. Control plants were well watered during the experimental periods. The long-term water stress without rewatering decreased the chlorophyll content, Chl a/b ratio, carbonic anhydrase (CA) activity, net photosynthetic rate (A), and leaf area compared with the control. Rewatering increased the ratio of Chl a/b, CA activity and A, but decreased the leaf area and ion leakage from the cut leaf pieces. The long-term water stress without rewatering reduced the maximal efficiency of PSII (F_v/F_m), the actual quantum yield (Φ_p), and photochemical quenching (q_p), but these values were increased by rewatering to more than the control level, though non-photochemical quenching (q_N) was decreased as compared with the control. This implied that long-term drought aggravated PSII, but rewatering improved it. The net CO₂-exchange rate showed similar diurnal changes in all treatments, but the rate in the morning was lower in long-term drought (before rewatering) than in the other treatments. These results suggest the photosynthesis of Leymus chinensis may be well adapted to episodical soil drought.     

水氮措施影响夏玉米氮素利用的叶绿素荧光特性研究

以产量差异显著的两个夏玉米品种德单5号和郑单958为材料,设不同灌溉和施肥水平,开展水氮互作对玉米产量、氮素利用和叶绿素荧光特性的影响研究。结果表明,在不同灌溉处理下,增施氮肥显著提高营养器官氮素转运量,降低氮素转运效率,N3(180 kg/hm²)、N4(225 kg/hm²)处理间无显著差异。增施氮肥也显著提高了各灌溉条件下两个品种吐丝期穗位叶F_v/F_m和F_v/F_o,当氮肥施用量增加至N3(180 kg/hm²)后增肥效果不显著。因此,大喇叭口期和吐丝散粉期分别灌溉37.5 mm配合180 kg/hm²的施氮量有利于提高叶绿素荧光参数F_v/F_m和F_v/F_o,促进夏玉米植株氮素转运,提高氮肥利用效率。此外,F_v/F_m和F_v/F_o均与植株氮...     

不同基因型玉米自交系苗期干旱-复水的生理响应机制

采用称重控水法模拟干旱胁迫,设对照和胁迫两个处理,在3叶期对24个玉米自交系叶片相对含水量(RWC)、游离脯氨酸(Pro)等生理指标进行测定,研究玉米的抗旱机理及复水补偿效应机制。结果表明,干旱胁迫下玉米叶片相对含水量、叶绿素荧光参数(F_v/F_m)和叶绿素含量(Chl)与对照相比显著下降,游离脯氨酸(Pro)、超氧化物歧化酶(SOD)和氧化物酶(POD)明显上升,复水后不同基因型自交系各生理指标表现出不同程度的补偿效应。利用隶属函数法将D17982、郑H71、PH4CV、昌7-2和L269等14份自交系归为抗旱性较强的自交系,PH4CV、HCL645、D17982、郑7314、郑H71和郑9712这6份自交系归为复水恢复能力强的自交系。     

小麦苗期叶片碳氮平衡与低氮诱导的叶片衰老之间的关系

为了解小麦叶片衰老与缺氮诱导及碳氮平衡之间的关系,以两个缺氮衰老响应敏感品种(周麦24和运旱618)和两个缺氮衰老响应不敏感小麦品种(衡观35和西农979)为材料,分析了小麦苗期低氮诱导下表征叶片衰老的叶绿素含量、F_v/F_m、净光合速率,以及表征碳氮平衡的全氮和非结构性碳水化合物(可溶性糖、淀粉)比值。结果表明,低氮胁迫后,4个小麦品种叶片的净光合速率、叶绿素含量和F_v/F_m显著降低,说明低氮诱导和加速了小麦叶片的衰老,而缺氮衰老响应敏感品种的衰老程度显著高于不敏感品种。缺氮衰老响应敏感和不敏感小麦品种叶片氮含量在低氮胁迫后均显著降低,同时碳累积量(可溶性糖和淀粉含量)均显著升高。进一步分析表明,缺氮诱导的小麦叶片衰老可能并非受独立的氮缺乏和碳累积调控,而可能与碳氮平衡(碳氮比例)有关,即碳氮平衡可能参与了低氮诱导的叶片衰老调控,而缺氮下耐衰老品种的叶片维持碳氮代谢平衡的能力较强。     

高光、水分和盐胁迫下小麦光合特性和抗氧化酶系统的比较

为了解植物光合机构及抗氧化酶系统对高光、水分及盐胁迫的适应机制,比较分析了光强1 800 μmol·m^-2·s^-1、20% 聚乙二醇（PEG-6000）和0.3 mol·L^-1 NaCl处理下小麦叶绿素荧光以及抗氧化酶活性的变化。结果表明,与对照相比,高光胁迫、水分胁迫和盐胁迫下小麦叶片相对含水量、总蛋白含量以及叶绿素含量均下降,以水分胁迫效应最显著,盐胁迫次之。三种胁迫均显著降低了小麦叶片的光合速率、气孔导度、蒸腾速率、PSII最大光化学效率（F_v/F_m）及电子传递率（ETR）,而显著增加胞间CO₂浓度、非光化学淬灭（NPQ）、脯氨酸及可溶性糖含量,也以水分胁迫效应最显著。三种胁迫下小麦叶片内的超氧化物歧化酶（SOD）、过氧化物酶（POD）及过氧化氢酶（CAT）活性随胁迫时间的延长呈现不同的变化趋势。其中,SOD活性在三种胁迫下均呈先升后降的趋势;POD活性在高光和水分胁迫下先升后降,而在盐胁迫下呈上升趋势;CAT活性在高光和盐胁迫下呈上升趋势,而在水分胁迫下呈下降趋势。以上结果表明,在三种环境胁迫中,水分胁迫给小麦带来的伤害最严重,盐胁迫次之,高光胁迫最轻。 此外,小麦抗氧化酶系统在高光胁迫、水分胁迫及盐胁迫下应答机制不同。     

Correlation of Chlorophyll Meter Readings with Gas exchange and Chlorophyll Fluorescence in Flag Leaves of Rice (Oryza sativa L.) Plants

Abstract

The objective of this study was to establish the correlation of the chlorophyll meter (SPAD) readings with the contents of chlorophyll (Chl) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the gross photosynthetic rate (P_g), and the maximum quantum yield of photosystem II (PSII) (F_v/F_m) in flag leaves of rice (Oryza sativa L.) in ripening stage. The SPAD readings significantly correlated with the Chl content, the Rubisco content, P_g and F_v/F_m (R² = 0.848, 0.648, 0.671 and 0.712, respectively), which suggests that the SPAD meter has the potential to estimate the photosynthetic capacity of the flag leaves. However, both P_g and F_v/F_m had a stronger relationship with the Rubisco content than the SPAD readings, indicating that the PSII photochemical and CO₂ assimilation capacities are strongly influenced by the Rubisco content. Therefore, accurate calibration would be indispensable to obtain the physiological information from the SPAD readings of flag leaves.     

Effects of drought on chlorophyll fluorescence in potato (Solanum tuberosum L.). I. Plant water status and the kinetics of chlorophyll fluorescence

Summary The slow kinetics of chlorophyll fluorescence were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Constant and variable fluorescence (F _o andF _v respectively) declined with time in plants from both irrigated and droughted treatments, but the decline was greater in droughted than irrigated plants. However, the yield of variable fluorescence (F _v/(F _o+F _v)) was unaffected by the drought treatment. The main effect of drought was upon the quenching of variable fluorescence. Both the half life of the decay of variable fluorescence (q_1/2) and the secondary maximum (M) were significantly greater in the droughted plants than in those from the irrigated treatment. Significant differences between genotypes were found forF _v/(F _o+F _v),M andq _1/2. Genotype-by-treatment interactions were non-significant for all the variables examined. Changes in chlorophyll fluorescence transients were not closely related to changes in leaf water potential.     

氮肥对半干旱区膜下滴灌玉米叶片叶绿素荧光特性及产量的影响

针对吉林省西部半干旱区的生态特点,研究氮素营养水平对膜下滴灌条件玉米净光合速率、叶绿素荧光参数、光合酶活性和产量的影响。结果表明,适宜的氮肥施用量可显著提高叶片光合性能,随着氮肥施用量的逐渐增加,叶片气体交换参数也逐渐升高;当氮肥超过300 kg/hm2时,各项指标开始下降。在荧光诱导动力学参数中,最大光化学效率(Fv/Fm)对种植模式的改变比较敏感,膜下滴灌下各处理平均Fv/Fm均显著高于同期普通生产田对照,随着施氮量的增加Fv/Fm增加;高氮处理穗位叶Fv/Fm无显著差异。施用氮肥均增加了玉米穗位叶PEP和Ru BP羧化酶活性。在膜下滴灌模式下,玉米达到最高产量时的氮肥施用量为200 kg/hm2,与300 kg/hm2时的产量无显著差异;非膜下滴灌玉米获得最高产量时的施氮量为300 kg/hm2。     

干旱条件下我国不同年代玉米品种保绿性比较

选用35个玉米品种(农家种4个, 双交种4个, 单交种27个), 在海南三亚设置正常浇水和花期干旱两个处理, 鉴定每个品种在干旱环境下的保绿性, 比较不同年代品种的持绿性。结果发现, 干旱导致玉米叶片叶绿素含量下降, 衰老启动时间提前, 干旱条件下品种的衰老启动时间、最大衰老速度出现时间均随年代更替而延后, 最大衰老速度均随着年代更替而下降, 即玉米的保绿性均随着年代更替而提高, 与正常浇水条件下的趋势相似。玉米保绿性与叶绿素含量均与产量呈显著相关;在干旱处理条件下, 品种保绿性均随年代更替而提高, 我国的玉米育种中已经对持绿性进行了改良, 耐旱性也得到提高。     

冬前镇压和灌溉对冬小麦灌浆期旗叶光合特性和叶绿体超微结构的影响

为明确冬前镇压和灌溉对冬小麦灌浆期旗叶功能的影响,以济麦22为材料,在2016-2017小麦生长季,对其进行冬前镇压+灌溉(C+I)、灌溉(I)和镇压(C)处理,以常规种植管理为对照(CK),研究不同冬前栽培措施对冬小麦灌浆期土壤微环境、旗叶光合特性和叶绿体超微结构以及最终产量和生物量的影响。结果表明,与CK相比,C、I及C+I处理都可提高麦田土壤含水量和土壤温度,可增加花后14～28d旗叶叶绿素相对含量(SPAD)、灌浆期旗叶最大光学效率(Fv/Fm)、净光合速率(Pn)和蒸腾速率(Tr),缓解旗叶SPAD、Fv/Fm、Pn和Tr在灌浆后期的下降,其中以C+I处理的效果最佳;灌浆中后期(花后21d),CK条件下小麦植株旗叶部分叶绿体呈圆形,大部分基粒片层变形且排列紊乱,可见较多的亲锇颗粒,但C+I、C和I处理下叶绿体的破坏程度降低,较多的叶绿体呈椭圆形,单位面积内叶绿体数和叶绿体基粒数提高,基粒片层较CK清晰且排列紧密,亲锇颗粒数量减少,其中C+I和I处理对叶绿体超微结构的改善作用大于C处理。这说明在本试验条件下,冬前镇压+灌溉较单独灌溉或镇压更有利于改善小麦灌浆期旗叶光合功能,缓解灌浆后期旗叶的衰老,促进小麦产量形成。     

Growth and Physiological Performance of Aerobic and Lowland Rice as Affected by Water Stress at Selected Growth Stages

Aerobic rice technology is still new in Malaysia, and information regarding MARDI Aerob 1 (MA1), the first local aerobic rice variety, is still lacking. Therefore, comparative studies were carried out to determine the physiological performance of aerobic rice variety MA1 and lowland rice variety MR253 under water stress given at the panicle initiation, flowering and ripening stages. This experiment was arranged in a randomized complete block design. Stomatal conductance (g_s), chlorophyll a fluorescence (F_v/F_m), leaf relative water content (leaf RWC), and soil moisture content (SMC) as well as yield component parameters such as panicle number, grain yield and 100-grain weight were measured. Results revealed that g_s and leaf RWC for both varieties decreased with depletion of SMC. The correlation study between the physiological parameters and SMC indicated that F_v/F_m was not affected by water stress, regardless of varieties. The yield components (panicle number, grain yield and 100-grain weight) for both varieties greatly decreased when water stress was imposed at the panicle initiation stage. This study showed that the panicle initiation period was the most sensitive stage to water stress that contributed to a substantial reduction in yield for both varieties. Under the aerobic condition (control), MR253 produced higher panicle number, 100-grain weight and yield than MA1. Although MR253 is bred for lowland, it is well adapted to aerobic condition.     

Germination responses of the halophyte Chloris virgata to temperature and reduced water potential caused by salinity,alkalinity and drought stress

Chloris virgata is considered a useful grass species for grassland restoration in northern China. However, little information exists concerning the germination responses of this species to temperature and water potential caused by stress conditions. Experiments were conducted in growth chambers to assess the effect of temperature, salinity, alkalinity, drought and the interactions of temperature and stress on seed germination. Seeds were germinated at three diurnal temperature regimes, with four water potentials in NaCl, NaHCO₃ and PEG solutions. Results showed that optimal germination under stress occurred at 15–25 °C, and germination percentages and rates were inhibited by either an increase or decrease in temperature from the optimal temperature. The inhibitory effects of the low water potential caused by salinity and drought on germination were greater at 25–35 °C, but seeds were subjected to more stress despite the relatively higher water potential because of the alkalinity at this temperature. The recovery percentage under salinity was highest at ?1·2 MPa at 15–25 °C, and more than 80% of seeds also germinated at this water potential after they were transferred from drought stress. However, seeds lost their viability in higher alkalinities under all temperatures, and at 25–35 °C, there was lower recovery percentage under stress. Results suggest that salinity, alkalinity and drought stress have different impacts on seed germination, and the tolerance to stress of C. virgata seeds is affected by the interactions of temperature and water potential caused by salinity, alkalinity and drought. Chloris virgata shows potential utility as a promising grass species in salinity–alkalinity and drought‐stressed environments.     

不同类型小黑麦产量形成的光合特性差异

为了明确不同类型小黑麦产量形成的光合特性,以加工型品种东农8809、饲用型品种东农5305和粮饲兼用型品种东农96026为材料,采用随机区组试验,探讨了不同类型小黑麦主要生育阶段叶绿素荧光参数、光合参数、叶绿素相对含量以及产量的差异。结果表明,加工型品种东农8809生育后期PSⅡ最大光化学效率下降幅度大,非光化学系数高,光能消耗大,籽粒产量形成受到限制;饲用型品种东农5303扬花前光合能力较强,生物产量潜力高,花后非光化学淬灭系数增加量大,花后叶绿素相对含量迅速下降,叶片衰老快;粮饲兼用型品种东农96026净光合速率高,开花后叶绿素相对含量降幅小,叶片衰老慢,光化学淬灭系数高,PSⅡ电子传递活性大,成熟期最大荧光产量和最大光化学效率大及籽粒产量潜力高。说明不同类型小黑麦光合特性不同,花后较强的光合能力是籽粒产量高的基础;对于粮饲兼用型小黑麦来说,较小的热耗散释放比例及较高的花后光合能力是其以大穗实现较高籽粒产量的途径。     

野生二粒小麦根中干旱响应蛋白的分离与鉴定

为了解野生二粒小麦响应干旱胁迫的调控机制,分析了干旱胁迫下小麦根的相对含水量、丙二醛、脯氨酸和过氧化氢含量,采用双向电泳(2-DE)结合MALDI-TOF-TOF-MS方法分离和鉴定了野生二粒小麦根中干旱响应蛋白的变化。结果表明,随着干旱处理时间的延长,野生二粒小麦根的相对含水量下降,脯氨酸含量先上升后降低,过氧化氢含量和丙二醛含量上升;复水后的野生二粒小麦根的相对含水量、脯氨酸含量有所升高,但未达到对照的水平。通过对干旱处理6d后根系的总蛋白进行双向电泳分离和MALDI-TOFTOF生物质谱鉴定,成功鉴定出26个差异表达蛋白,13个上调表达,13个下调表达。26个差异表达蛋白的功能主要涉及信号传导、氧化解毒、碳代谢、能量代谢、蛋白质生物合成及细胞骨架稳定。推测野生二粒小麦为适应干旱胁迫,通过根部感应胁迫信号,并传导至细胞内,影响小麦根中蛋白质的生物合成、氨基酸代谢、碳水化合物代谢、细胞骨架形成;通过抗氧化酶系统和抗氧化物质的作用,将过多活性氧加以清除;通过增加胞内脯氨酸含量,降低根中水分损失。     

干旱胁迫下披碱草属种间杂种F1的DNA甲基化MSAP分析

为了研究披碱草属种间杂种抗旱性优势的遗传机理，以加拿大披碱草（J1）、老芒麦(L1)及其种间杂种F₁为试验材料，经干旱胁迫处理，采用甲基化敏感扩增多态性（MSAP）方法，探究干旱胁迫后亲本及种间杂种F₁的DNA甲基化变化规律。结果表明，亲本材料L1和J1的DNA平均甲基化水平分别为45.41%和59.53%，杂种F₁的DNA甲基化水平为44.24%，说明杂种在形成过程中发生了DNA去甲基化作用。全甲基化在杂交种的DNA甲基化模式中占主导地位。干旱胁迫前亲本L1、J1和杂种F₁的DNA甲基化程度分别为32.73%、41.54%和28.00%，杂种F₁甲基化水平为亲本材料的75.40%；干旱胁迫后各材料的DNA甲基化程度均增加，平均增幅分别为14.99、20.44和19.78个百分点，说明干旱胁迫对不同材料DNA甲基化水平均有明显影响，且具有特异性。杂种F₁的抗旱性最强，其DNA甲基化水平低于亲本，说明杂交种的抗旱性与DNA甲基化水平存在一定的负相关。