农业废弃物资源化利用是防治农业面源污染、改善农业生产环境的有效途径;同时,也是改善农村人居环境,推动生态宜居美丽乡村建设的重要内容.基于黑龙江、山东、河南、四川4省684个样本农户数据,运用多元排序Probit模型分析了农户农业废弃物资源化利用参与意愿及其影响因素,并通过控制相关变量进行了稳健性检验.结果表明,政府监管并不能提高农户参与农业废弃物资源化利用的意愿,而前景预期、政策了解度、农业废弃物资源化补贴、设立固定回收点或与回收企业合作、合作社参与等因素更能提高农户的参与意愿.为此,可以采取发挥非经济预期的作用、构建财政补贴机制、健全农业废弃物资源化回收利用机制、利用合作社平台等措施激发农户参与农业废弃物资源化利用的关键行为动机,提高农户参与农业废弃物资源化利用的意愿,推动农业绿色发展及乡村生态振兴.

为提高农户农业废弃物资源化利用意愿,改善农村生态环境,顺应农民对美好人居环境的期待,本文基于河南、山东、四川、黑龙江4省693个农户的调研数据,建立多元有序Logistics模型,研究农户农业废弃物资源化利用价值与技能感知、成本收益感知与市场回收条件感知对其参与意愿的影响,并引入环境规制政策作为调节变量,分析了环境规制政策对农户农业废弃物资源化利用感知-参与意愿关系的调节效应.结果表明:1)农户农业废弃物资源化利用技能感知、成本感知、与回收渠道间的距离感知、回收渠道稳定性感知,均显著地影响其参与意愿;其中,农户技能感知和回收渠道稳定性感知对其参与意愿具有显著的正向影响.2)引导型规制对农户农业废弃物资源化利用前景感知与技能感知-参与意愿关系存在显著的正向调节效应;约束型规制对农户农业废弃物回收利用重要性感知、回收渠道稳定性感知-参与意愿关系存在显著的正向调节效应;激励型规制对农户农业废弃物资源化利用前景感知与技能感知、收益感知、回收渠道稳定性感知-参与意愿关系存在显著的正向调节效应,对与回收渠道间的距离感知-参与意愿关系存在显著负向调节效应.建议加强技术培训、增设更多补贴款项、健全农业废弃物回收机制,提高农户参与意愿,充分发挥3种规制政策的互补作用,不断调整优化农业废弃物资源化利用政策,持续推进农业农村绿色发展.

实现农业绿色发展,对保障国家粮食安全、提高安全优质农产品供给能力、满足人们日益增长的美好生活需要具有重要意义.运用改进的熵值法,基于2003～2017年我国13个粮食主产省份的面板数据,对其农业绿色发展水平进行评价,并利用多指标面板数据的聚类分析方法对2003～2017年13个粮食主产省份农业绿色发展水平予以分类分析,考察粮食主产区各省份之间的差异性.结果 表明:2003年以来,粮食主产区农业绿色发展总体水平明显提高,13个省份农业绿色发展各有短板和优势,省份间农业绿色发展水平和速度差异较大.提升粮食主产区农业绿色发展水平,应着重弥补农业绿色发展过程中的短板,缩小粮食主产区各省份间差距;加强农业绿色发展战略的顶层设计和机制构建,建立完善的奖惩机制和预警机制;引导多元主体共同参与推动农业绿色发展.

探讨了Ca2+和H2S调节小麦干旱胁迫的交互关系.结果表明,H2S和Ca2+均可缓解干旱胁迫诱导的氧化伤害,与干旱处理组相比,H2S和Ca2+预处理显著降低了叶片中丙二醛(MDA)和H2O2含量,提高了超氧化物歧化酶(SOD)活性,减少了干旱胁迫对过氧化物酶(POD)和过氧化氢酶(CAT)活性的诱导,但乙二醇双(2-氨基乙基醚)四乙酸(EGTA,钙螯合剂)处理显著削弱了H2S对干旱胁迫的缓解作用,而亚牛磺酸(HT,H2S清除剂)处理对干旱胁迫下Ca2的缓解作用没有影响.此外,干旱胁迫下,H2S可诱导Ca2+信号途径相关基因表达(如CcaMK,CPK10,CIPK2和CIPK15),而Ca2+对小麦叶片内源H2S含量无显著影响.由此推测,Ca2+可能位于H2S信号的下游,部分介导了H2S对小麦干旱胁迫的调节作用,H2S可通过促进Ca2+信号途径相关基因的表达调节干旱胁迫.

以烤烟品种K326为材料,设置D1 (16 592株·hm-2)、D2 (18 182株·hm-2)、D3 (20 202株·hm-2)3个种植密度处理,采用15N标记技术,研究烤烟对氮素吸收与分配的特点,以及种植密度的调节效应,结果表明:圆顶期烟株各部位吸收的肥料氮(Ndff)比例表现为下部叶＞中部叶＞茎秆＞上部叶＞根系,说明在圆顶期烟株下部叶和中部叶对来自肥料的15N的征调能力较强,但随着烟株的发育和成熟衰老,各部位对肥料氮的吸收征调能力逐渐下降.种植密度对烟株不同部位的Ndff比例具有显著影响,增加种植密度提高了圆顶期各部位的Ndff比例,但到了中后期,随着种植密度增大,烟株的Ndff比例明显下降,表明种植密度过大,不利于烟株生育中后期维持对氮素的征调能力.烟株各部位的15N分配率,圆顶期表现为下部叶＞中部叶＞上部叶＞茎秆＞根系,烟株吸收的15N平均76.95％分配到叶片、15.36％分配到茎秆、7.68％分配到根系,表明在生长发育前期烟株吸收的15N大部分向叶片分配,在D2处理的种植密度下烟株圆顶期15N向根、茎的分配率较高,有利于根、茎发育,形成健壮植株;在下部、中部叶片成熟采收后,叶片中的15N分配率降低,根、茎中的15N分配率上升,但直到生育后期仍以叶片的分配率较高.总体上氮肥利用率随着生育进程而降低,但各个时期均以D2处理的氮肥利用率最高,生育后期D2处理、D3处理之间的差异不显著.在试验设置的种植密度处理中,随着种植密度增大,烟叶产量增加,但上等烟的比例明显降低,以D2处理的单位面积产值最高,其后依次为D3处理和D1处理,说明适宜的种植密度为18 182株·hm-2,其对氮肥的利用率,以及烤烟品质和生产效益均较高.

Cysteine desulfhydrase (CDes) can catalyze the degradation of cysteine producing hydrogen sulfide. In this study, d-cysteine desulfhydrase from wheat (TaD-CDes) was cloned and overexpressed in Arabidopsis thaliana. The physiological effects of TaD-CDes were determined by investigating seed germination, root growth, stomatal closure, and drought resistance in the TaD-CDes plants. Results showed that, compared with wild-type plants (WT), seed germination, root growth, and stomatal closure of the TaD-CDes plants were more sensitive to ABA, resulting from up-regulation of ABA-responsive genes (such as PYR1, ABI1, ABI2, HAB1, HAB2, SnRK2, ABF2, and ABF4). Moreover, although TaD-CDes mediated ABA-induced stomatal closure, TaD-CDes-overexpressing plants did not show higher drought resistance than WT, which might be attributed to their increased stomatal densities.

以小麦(Triticum aestivum L.)品种豫麦49为材料,研究了高温、干旱及高温干旱复合胁迫对小麦叶片RuBP羧化酶(Rubisco)、Rubisco活化酶(RCA)活性及Rubisco活化酶基因(Rca)表达的影响及外源一氧化氮(NO)的调节效应.结果表明,干旱和高温干旱复合胁迫导致小麦叶片的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性降低,而高温胁迫下SOD和CAT活性升高.NO预处理能显著增强干旱及高温干旱复合胁迫下的抗氧化酶活性.编码RCA不同亚基的基因(Rca a和Rca b)对不同逆境胁迫的响应存在差异,干旱、高温和高温干旱复合胁迫导致Rca a基因的表达水平分别降低97％,92.31％和84.93％,Rca b的转录水平则在高温和高温干旱复合胁迫下分别比对照升高了26.14和28.02倍.NO预处理使干旱胁迫下Rca a的表达增加了38.42倍,Rca b的表达增加了32.74倍,使高温干旱复合胁迫下Rca b的表达水平提高了30.39％.遭受干旱、高温及二者复合胁迫后,小麦叶片的RCA活性、Rubisco初始活性、总活性以及Rubisco活化状态明显下降,而采用NO预处理不同程度地提高了干旱、高温及高温干旱复合胁迫下小麦叶片的RCA活性及Rubisco酶的初始活性、总活性与活化状态,使其在逆境下保持较高的叶绿素含量(SPAD值)和光合速率.总之,NO能够通过增强抗氧化酶活性和调节Rca基因表达,提高RCA和Rubisco活性,缓解高温干旱复合胁迫对小麦叶片的光合作用的损伤.

为了探究5-氨基乙酰丙酸(5-aminolevulinic acid,5-ALA)对干旱胁迫下小麦幼苗光合作用损伤的缓解机制,选用矮抗58小麦品种为试验材料,在两叶一心期对叶片喷施浓度为100mg/L的5-ALA,处理3d后对根部施加20％聚乙二醇6000(PEG-6000)模拟干旱环境,2d后取样进行光合以及psbA基因表达分析和D1蛋白含量测定.结果表明,干旱胁迫明显降低了小麦叶片的相对含水量以及叶绿素含量,而喷施外源5-ALA能够明显缓解干旱造成的伤害,同时也减缓了干旱胁迫下小麦幼苗净光合速率(Pn)、实际光化学效率(ΦPSⅡ)、原初光化学效率(Fv/Fm)和光化学猝灭系数(qP)值的降低,以及非光化学猝灭系数(qN)值的升高,并且提高了psbA基因表达水平和D1蛋白的含量.以上结果显示,喷施外源5-ALA可缓解干旱胁迫下小麦幼苗的光合性能,同时诱导psbA基因表达水平提高,加快新D1蛋白的合成与受损D1蛋白的降解,从而提高小麦幼苗的干旱胁迫耐受性.

Heat stress is one of the main abiotic stresses that limit plant growth. The effects of high temperature on oxidative damage, PSII activity and D1 protein turnover were studied in three wheat varieties with different heat susceptibility (CS, YN949 and AK58). The results showed that heat stress induced lower lipid peroxidation in AK58 and YN949 than CS, which was related to different changes of SOD, CAT, POD and H 2 O 2 . Similarly, AK58 and YN949 performed better PSII photochemical efficiency (F v /F m , ΦPSII and ETR) under high temperature, which was attributed to rapid synthesis and degradation of D1 protein. Moreover, higher expression of D1 protein turnover-related genes ( PsbA , STN8 , PBCP , Deg1 , Deg2 , Deg5 , Deg8 , FtsH1/5 and FtsH2/8 ) and SOD activity in AK58 and YN949 under normal conditions also established a basis for acclimatizing high temperatures, thereby alleviating PSII photoinhibition and reducing oxidative damage when exposed to heat stress.

Drought is an environmental factor that deeply impacts wheat yield and quality. Hydrogen sulfide (H2S) is a known regulator of drought resistance in plants. To preliminarily elucidate the regulatory mechanisms of H2S on drought tolerance, the effects of H2S on drought-responsive genes were investigated by transcriptome analysis. As a result, a total of 7552 transcripts not only responded to drought stress but also exhibited differential expression relative to the polyethylene glycol (PEG) treatment (P) and the NaHS pretreatment with PEG treatment (SP). GO categories of 'transport' were especially enriched under the SP treatment and ion transport categories (especially 'iron ion transport') were more significantly enriched among up-regulated transcripts in SP versus P treatments (SP.vs.P). Indeed, a higher translocation of iron from root to shoot and iron availability in shoots was detected in SP compared to P. The KEGG pathway of 'ribosome biogenesis in eukaryotes', 'protein processing in endoplasmic reticulum', 'fatty acid degradation', and 'cyanoamino acid metabolism' was induced by H2S under drought stress. Further, H2S was involved in plant hormones signal transduction, and drought-induced transcription factors, protein kinases, and functional genes exhibited higher expression levels under SP relative to P. Additionally, several effectors or master regulatory genes of H2S were identified genome-wide. Summarily, these results showed that H2S alleviated drought damage probably related to transport systems, plant hormones signal transduction, protein processing pathway, fatty acids and amino acids metabolism, which provides a guide for future experimentation to analyze hydrogen sulfide-dependent drought tolerance mechanisms in wheat.

Using K 326 (a cultivar of Nicotiana tabacum) as material,differences in capability of carbon assimilation between leaves at various positions,different areas of the same leaf and characteristics of assimilation product distribution in plants of flue-cured tobacco were studied by the method of 13C labeling.At the same time,the regulating effect of nitrogen application rate was investigated.The results showed that,at the same flue-cured tobacco plant,capability of carbon assimilation of middle leaves was the highest,followed by upper and lower leaves.In comparison with different areas of the same leaf,capability of carbon assimilation was the highest in the middle section,followed by base and top section.With the increment of nitrogen application rate,13C assimilative capability of upper and lower leaves had a tendency to increase,but the assimilative capability of middle leaves was the highest in treatment of moderate nitrogen application rate (N2).13C assimilated by leaves of various positions was allocated mainly to the corresponding leaves,root and stem.There was a trend that the transportation of 13C assimilation product to root and stem was promoted by the increasing of nitrogen application rate.

In present study,13C labelling method was used to evaluate the differences in carbon assimilation ability of leaves at different positions of flue-cured tobacco plants,the distribution characteristics of photosynthate,and the regulating effect of planting density.Three different treatments of planting density were designed and denoted as D1 (16 529 plants/ha),D2 (18 182 plants/ha) and D3 (20 202 plants/ha).The leaves at upper,middle and lower positions of tobacco plants were labeled with 13CO2 respectively at round top stage.As shown in the results,at the same flue-cured tobacco plant,the highest 13C assimilation capability was observed on middle leaves,followed by the upper and the lower leaves.In comparison with different areas of the same leaf,the highest capability of carbon assimilation was in the middle section,followed by the base and the top section.Averagely,19.71％ of 13C assimilation products of upper leaves were transported to root system,42.22％ to stem,and 38.07％ were left in leaves and most of them were left in upper labelled leaves.33.42％ of 13C assimilation products of middle leaves were transported to root system,26.00％ to stem,and 40.58％ were left in leaves and most of them were left in middle labelled leaves.33.67％ of 13C assimilation products made by lower leaves were transported to root system,23.72％ to stem,and 42.61％ were left in leaves and most of them were left in lower labelled leaves.In terms of assimilation product allocated to the stem,photosynthates of upper leaves were mainly distributed to middle part of stem,and photosynthates of middle and lower leaves were mainly distributed to base part of stem.The carbon assimilation capacity of leaves and the amount of assimilation product transported to root and stem both decreased along with the increase of planting density.Under the high planting density of D3,carbon assimilation capacity of leaves at all positions declined significantly.In conclusion,substance basis for the tobacco yield and quality mainly originates from the carbon assimilation by themselves during the growth of leaves.The planting density has a significant impact on the 13C assimilative capacity of flue-cured tobacco leaves.Under this experimental conditions,the planting density around 18 182 plants/ha is conducive to improving the carbon assimilation capacity and coordinating the assimilation product distribution in flue-cured tobacco.

Canopy photosynthetic capacity determines the yield and quality,while planting density affects the growth and canopy development of a flue-cured tobacco plant.Varied planting densities (i.e.,D1at 16 529 plants per hm2,D2 at 18 182 plants per hm2,and D3 at 20 202 plants per hm2) were applied to study their effect on the leaf area index (LAI),light transmittance (LT),photosynthesis,and economy of the canopies on Yunyan 85tobacco plants.The results showed that,during the entire course of canopy development,LAI was at its highest level and the distance between leaf tips of adjacent lines (DLT) and LT at their lowest in the dome stage.As the leaves matured and upon harvest,LAI declined,while DLT and LT increased.Consequently,the canopy photosynthetic rate(RCP) peaked during the dome stage.In comparison,in the same period,an increased planting density would induce a heightened LAI but lowered DLT and LT.On the other hand,the changes of planting density or leaf-harvesting did not significantly affect RCP on the plants.LAI was found inversely correlated to DLT and LT.The correlation between RCP and planting density varied at the dome stage.RCP raised as the density increased from D1 to D2,but decreased from D2 to D3.And,RCP correlated to leaf-removal,but insignificant.RCP could not be continually risen with increasing planting density.In fact,it declined when the density exceeded a certain level.Yield and output on tobacco leaves increased significantly as the planting density increased from D1 to D2,but decreased from D2 to D3.The percentage of high-grade tobacco was maximized with D2 among the 3 treatments.Taking the canopy development,field management and production cost together into consideration,a planting density approximating 18 182 plants per hm2seemed optimal for Yunyan 85 cultivation.

We examined the effects of 2,4-epibrassinolide (EBR) application on photosynthesis, antioxidant enzyme activity, and Rubisco activase (RCA) gene expression in wheat ( Triticum aestivum L.) seedlings under a combination of drought and heat stress. The net photosynthetic rates (P n ) of wheat seedlings decreased significantly, the photosynthetic capability was inhibited, and the activities of superoxide (SOD), peroxidase (POD), catalase (CAT), and RCA as well as the initial and total activity of Rubisco declined under the combined stress. These decreases and inhibitory effects were significantly ameliorated by exogenous EBR application. Three subunits (45–46, 41–42, and 38–39 kDa) of RCA were observed in wheat seedlings. The abundances of the 38–39 kDa and 41–42 kDa subunits were significantly lower in plants subjected to stressful conditions than in unstressed plants. Interestingly, a marked increase in 45–46 kDa RCA was observed under heat or heat combined with drought stress. The abundance of 38–39 kDa RCA in seedlings exposed to heat, drought, or their combination was significantly enhanced by EBR pretreatment, which paralleled the changes in initial Rubisco activity and P n , but was not consistent with observed mRNA abundance. These results indicated that the larger subunit of RCA (45–46 kDa), which is more thermostable and increased in response to moderate heat stress, and the smaller isoform (38–39 kDa) of RCA may play important roles in maintaining the photosynthetic capability by EBR under stress conditions.

Canopy photosynthetic capacity is the basis for the yield and quality of flue‐cured tobacco ;and ,nitrogen fertilization is critical in regulating the individual growth and canopy development of the plants .To determine the relationship between the fertilization and the canopy photosynthesis ,3 nitrogen fertilizer application rates ,i .e .,N 75.0 kg · hm-2 (N1 ) ,N 97.5 kg · hm -2 (N2 ) and N 120.5 kg · hm -2 (N3 ) ,were applied on the tobacco cultivation .The effects of the varied fertilizations on the leaf area index (LAI) ,light transmittance (LT ) ,and photosynthesis of K326 tobacco were monitored .The results showed that ,in the course of canopy development , LAI was the highest ,but the distance between leaf tips of adjacent lines (DLT ) and LT was the lowest at the round top stage ;and afterwards ,LAI decreased ,DLT and LT increased as the leaves were harvested .Meanwhile ,the canopy photosynthetic rate was the highest at the same stage ,and LAI in the order of N3 ,N2 and N1 ,with no statistically significant difference found between N 2 and N3 .After the lower leaves were harvested from the plants , LAI of N2 became greater than those of N2 and N3 .Additionally ,the leaf area duration of N2 was the longest among the treatments during the two periods from the round top stage to the lower leaves harvest ,as well as ,from the lower leaves harvest to the middle leaves harvest . The canopy LT of N3 was the lowest , with no significant difference between N1 and N2 ,and the canopy photosynthetic rate and canopy leaf source capacity of N 1 were the lowest with no significant difference between N2 and N3 . The tobacco yield increased with increasing nitrogen application .However ,the proportion of top‐quality tobacco and output value were found to be the highest under treatment N2 .Thus ,an intermediate nitrogen fertilization rate (approximately 97.5 kg per hm2 ) was considered economically appropriate for K326 cultivation at a planting density of 18 , 182 plants per hm2 as used in this experimentation .

To investigate the effect of exogenous progesterone on the activities of lipid peroxidation and antioxidant enzymes,the seedlings of maize (Zea may cv. Zhuyu 309) were pretreated with 10 -9 mol/L, 10 -7 mol/L,10 -5 mol/L,10 -3 mol/L of progesterone under the high temperature stress. The activities of superoxide dismutase ( SOD) ,catalase ( CAT) ,peroxidase ( POD) ,CAT and POD isozymes,and the ma-londialdehyde ( MDA) content,membrane permeability and chlorophyll fluorescence parameters of maize leaves were assayed. The results showed that,CAT activity of 10 -9 mol/L progesterone pretreatment was 2. 4 times higher than the high temperature treatment,and the activities of SOD and POD of 10 -7 mol/L progesterone pretreatment were 1. 1 times and 1. 2 times higher than the high temperature treatment,re-spectively. In addition,the relative electric conductivity of 10 -9 mol/L and 10 -7 mol/L progesterone pre-treatment decreased to 70% and 65% of the high temperature treatment,respectively; Malondialdehyde contents were also reduced to 69% or 74% of the high temperature treatment,respectively. The expression levels of POD and CAT isozymes of 10 -7 mol/L progesterone treatment elevated,as well as oxygen release rate and chlorophyll fluorescence paraments. This study showed that the pretreatment with 10 -9 mol/L and 10 -7 mol/L progesterone increased the activities of antioxidant enzymes,and decreased the MDA content and the electrolyte leakage rate under high temperature stress,thus to protect the photosynthesis in maize leaves.

试验以郑单958为材料,研究了不同沼液用量对夏玉米叶面指数、灌浆速率和产量构成因素的影响.结果表明:与对照和施氮肥相比,田间浇灌沼液不仅可以提高夏玉米叶面积指数和光合速率,而且可改善玉米的灌浆过程,从而增加了玉米穗粗、穗行数、穗粒数、穗粒重、千粒重和单位面积产量.3个不同沼液用量处理中,以T3效果最好,每公顷产量可达14006.7 kg,比对照增产40.7％.

Drought usually induces plant growth inhibition and oxidative damage. This report showed the protections of hydrogen sulfide (H2S) against drought-induced damage in wheat, which was manifested in the better growth, higher relative water content (RWC), lower thiobarbituric acid-reactive substances (TBARS), and hydrogen peroxide (H2O2) as well as the increased activities of superoxide dismutase (SOD) and catalase (CAT). Drought often causes photosystem II (PS II) damage, which was observed in the decreased potential photochemical efficiency (F v/F m), actual photochemical efficiency (ΦPS II), photochemical quenching (qP), electron transfer rate (ETR), and increased non-photochemical quenching (qN), however, these effects could be alleviated by NaHS (H2S donor). D1 protein in PS II reaction center is the most sensitive target of PS II damage. Compared to water treatment, a higher level of transcription but less D1 protein and phosphorylated D1 protein was detected in wheat leaves when exposed to NaHS under drought stress, which may result from the higher expression of STN8 (catalyze D1 protein phosphorylation) and D1 protein degradation-related gene (Deg1, Deg5, Deg8, FtsH2, and FtsH5). These results suggested that H2S alleviated drought-induced PS II damage owing to fast D1 protein turnover rather than D1 protein content.

干旱胁迫会抑制小麦种子的萌发及生长,20％聚乙二醇(PEG-6000)模拟干旱胁迫的同时施以不同浓度的外源葡萄糖处理小麦种子,探讨外源葡萄糖对干旱胁迫下小麦种子萌发及幼苗生长的影响.14 h光照/10 h黑暗的光周期培养条件下,较低浓度的葡萄糖(0.02 mmol/L和0.05 mmol/L)促进了干旱胁迫下小麦种子的萌发及幼苗生长,但较高浓度的葡萄糖(0.1 mmol/L,0.2 mmol/L及0.5 mmol/L)加强了干旱胁迫对小麦种子萌发及幼苗生长的抑制效应;而在黑暗条件下培养,葡萄糖的上述调节作用消失.以上结果说明葡萄糖对干旱胁迫下小麦种子萌发及幼苗生长的调节作用具有浓度效应,并且依赖于光.

This experiment was conducted to test the effects of foliar application of progesterone on the photochemical efficiency of photosystem II (PSII) and photosynthetic rate in wheat flag leaves subjected to cross-stress of heat and high light during grain-filling stage. The results showed that progesterone pretreatment increased the activities of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, and the contents of ascorbic acid and glutathione under the cross-stress. Meanwhile, the rate of O2 − production, hydrogen peroxide (H2O2) and malondialdehyde contents in progesterone pretreated leaves were significantly lower under heat and high light stress. In parallel with the alleviation of oxidative stress, higher content of D1 protein in PSII reactive center was observed in progesterone pretreated leaves, resulting in a significant increase in the potential (Fv/Fm) and actual (ΦPS II) photochemical efficiency of PSII, and the net photosynthetic rate. In summary, this study suggested that foliar application of progesterone might protect the PSII complex from heat and high light stress-induced damage through enhancing antioxidant defense system and further facilitating D1 protein stability in the wheat leaves.