Mixed salt stress significantly inhibits pepper germination and seedling growth, but it is unclear whether the negative effect can be mitigated by selenium (Se) addition. Four pepper varieties with large differences in salt tolerance were used as materials in this study. Based on the significant stress of mixed salts, the concentration of sodium selenite was set to 0, 5, 10, 20, 40, 80, and 120 µmol L− 1, respectively. Various parameters related to seed germination, seedling growth and development, as well as internal physiological indicators were measured, and the alleviating effects of sodium selenite on salt stress was comprehensively evaluated by fuzzy membership function method. The results showed that with the increase of sodium selenite concentration, the germination rate, relative salt damage mitigation rate, root fresh weight, fresh weight above ground, root length, hypocotyl length, and seedling activity index all showed an initial increase followed by a decrease, while the contents of superoxide anion radical (O2−), malondialdehyde (MDA), proline (Pro) and the activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) decreased first and then increased. On the whole, the total weighted values of membership function values of each index of the four varieties increased first and then decreased with the increase of sodium selenite concentration. The addition of appropriate concentration of exogenous sodium selenite (10–20 µmol L− 1) significantly improved seed germination of pepper, meanwhile, it alleviated the effect of salt stress and promoted root and above ground growth by significantly reducing the content of O2− and MDA. The appropriate concentration of exogenous Se could promote the growth and development of pepper seedlings and ensure the cultivation of strong seedlings by promoting the early and rapid germination of seeds and reducing the degree of stress.

[目的]研究喷施赤霉素缓解多效唑对叶用莴苣幼苗抑制作用.[方法]采用叶用莴苣不同品种与不同质量浓度的赤霉素进行双因素完全随机试验设计,采用5 个叶用莴苣品种,赤霉素质量浓度以有效成分计,分别设A1(0 mg/L)、A2(15 mg/L)、A3(30 mg/L)、A4(60 mg/L)、A5(120 mg/L)、A6(240 mg/L)和A7(480 mg/L)共7 种喷施水平,于叶用莴苣移栽期测定幼苗素质、叶形及叶片可溶性固形物含量.[结果]随赤霉素质量浓度增加,各叶用莴苣品种的株高、根鲜重、根干重、地上部鲜重、地上部干重、总叶面积、总叶长、总叶宽、最大功能叶叶长及最大功能叶叶宽均先增后降,各指标值均在A5 处理时达最大,与A1 处理相比,A5 处理各指标分别增加 36.8%～86.6%、30.1%～53.4%、21.1%～77.7%、56.2%～127.3%、56.0%～115.5%、63.4%～142.1%、30.4%～79.5%、27.0%～65.7%、24.0%～50.0%及 21.8%～48.8%.可溶性固形物也呈现先增后降的趋势,以A2 处理、A3 处理表现最佳.叶用莴苣各品种SPAD值及根冠比先降后增,各指标值均为A5 处理最低,与A1 处理相比,A5 处理各指标分别降低 17.6%～28.6%及 17.5%～36.2%.[结论]喷施赤霉素具有缓解多效唑抑制的作用,其中赤霉素质量浓度在A5(120 mg/L)时对叶用莴苣幼苗的调控效果最佳.

于2021年采集了赣州市设施菜地耕层(0～20 cm)235份土壤样本,测定了其土壤pH值、电导率、全氮、碱解氮、有机质、速效钾、有效磷等理化性质.结果表明:设施菜地耕层土壤的pH值平均值为5.3(3.7～6.9)、电导率为329.0(25.9～1889.0)μS/cm,土壤养分指标全氮、碱解氮、有机质、速效钾、有效磷含量分別为1.5(0.4～2.9)g/kg、139.2(42.7～319.1)mg/kg、26.8(10.0～42.2)g/kg、250.0(32.9～763.9)mg/kg、53.6(14.5～171.1)mg/kg,土壤综合肥力指数为1.51(0.78～2.34).在土壤pH值方面,有64.2%的样本处于强酸或酸性水平,仅赣南东北区域的土壤酸化程度相对较轻;在电导率方面,有86.8%的样本为低盐度及以下水平(＜600 μS/cm),土壤全氮、碱解氮、有机质、速效钾和有效磷的样本处于中等及以上含量水平分别有83.0%、88.1%、79.6%、67.7%和48.9%,其中,土壤有效磷在赣南西北部和东北部较大区域处于低或较低的含量水平;土壤综合肥力指数的样本为中等、肥沃水平分别有83.8%、15.7%.综上,赣南设施菜地土壤全氮、碱解氮和有机质总体较为丰富且盐渍化风险低,但酸化较为严重,有效磷有所亏缺,速效钾因区域而异,土壤综合肥力中等,应加强各土壤理化因子的协同提升.

以南方鲜食枣——麻姑鲜枣1号为对象,研究不同光照强度与避雨措施对枣树嫁接苗茎生长粗度、高度,嫁接苗成活率、成苗率,枣吊苗的变化.结果表明:100％光照+避雨对茎粗生长较快,100％光照+不避雨对茎高增长最快;40％光照+避雨对茎粗生长最慢,40％光照+不避雨对茎高生长最慢;避雨栽培苗木的均匀度较一致.避雨对嫁接枣苗的成活率、成苗率及枣吊苗的生长影响较大;光照对嫁接枣苗的成活率影响较小,但光照对后期苗高和茎粗生长有一定影响.生产实践中,通过避雨处理可有效提高嫁接枣苗的成活率与成苗率,降低枣吊苗的发生.

细胞分裂素具有促进植物细胞分裂等作用,能否通过喷施细胞分裂素来提高生菜穴盘育苗质量目前尚不明确.设品种与细胞分裂素浓度双因素完全随机试验,生菜供试品种分别为玻璃生菜、耐抽苔生菜、罗马直立生菜、香港软尾生菜、奶油生菜,细胞分裂素浓度(以产品重量计)分别设A1(0g/L)、A2(0.35 g/L)、A3(0.7 g/L)、A4(1.4 g/L)和A5(2.8g/L)共5种喷施水平.2020年探讨了穴盘基质育苗下苗期不同浓度细胞分裂素对南方生菜幼苗素质、叶型及地上部可溶性固形物含量的影响.随细胞分裂素浓度增加,各品种幼苗根冠比均呈先降后增趋势.而各品种幼苗株高、SPAD值、单株根鲜重、根干重、地上部鲜重、地上部干重、单株总叶面积、单株总叶长、单株总叶宽、最大功能叶叶长、最大功能叶叶宽及地上部可溶性固形物含量却均呈先增后降.其中耐抽苔生菜和香港软尾生菜的上述指标均在喷施1.4 g/L细胞分裂素(A4)时最高,而其他品种在喷施0.7 g/L细胞分裂素(A3)时表现最佳.苗期喷施适宜浓度细胞分裂素可显著提高生菜幼苗素质、叶型参数及地上部可溶性固形物,其中耐抽苔生菜和香港软尾生菜以A4(1.4 g/L)时生长发育表现最好,而奶油生菜、罗马直立生菜及玻璃生菜却在A3(0.7 g/L)时生长发育达到最佳.

去年春节,亲戚团聚,围绕着餐桌,我们吃起了团圆饭,好不热闹.按照惯例,待烧香后,爷爷和我们讲起了他儿时与粮食的故事,"我们小时候连饭都吃不上,虽然种了稻,可是收成也不多,常常吃红薯、野菜等食物艰难地填饱肚子……"."是呀,到了我们那个年代,粮食收成好点,才基本可以吃饱,每天盼的就是过节时吃点鱼肉",爸爸感慨道."对呀,哪像你们,物质富足,追求的就是如何吃好,可你们知道吗?要不是袁隆平研究出了杂交水稻,我们国家的粮食还是不够吃啊",大伯插了一嘴."是呀,他们这些小孩可都太幸福了……",长辈的附和声此起彼伏.

袁隆平先生,亲身经历了 20世纪60年代的大饥荒,为了人民不再忍受饥饿,决定去研究杂交水稻,只为让中国的老百姓都能吃上大米.袁隆平先生一直坚持着个人的"禾下乘凉梦"及"杂交水稻覆盖全球梦",他不断开拓创新、攻坚克难,将一生都贡献在研究杂交水稻上,他不负众望实现了问稻田要粮为国家增粮的伟大成就,解决了人民的温饱问题,并最终将个人梦想与保障国家粮食安全战略二者紧密联系[1].

To determine the salt tolerance and physiological mechanism of pepper (Capsicum annuum L.) at the germination stage, the Hongtianhu 101 and Xinxiang 8 varieties, which have large differences in salt tolerance, are employed as the study materials. Six mixed salt concentrations of 0, 3, 5, 10, 15, and 20 g/L derived using equal molar ratios of Na2CO3, NaHCO3, NaCl, CaCl2, MgCl2, MgSO4, and Na2SO4 are used. To determine their effects, the related indexes of seed germination, seedling growth, and physiology are measured, and salt tolerance is comprehensively evaluated using membership function analysis. The results show that as the mixed salt concentration increases, the germination potential, germination index, germination rate, seed germination vigor index, root length, and root fresh weight of the two cultivars significantly decrease, whereas the relative salt rate gradually increases. The hypocotyl length and fresh weight aboveground increase first and then decrease, while the malondialdehyde (MDA), proline (Pro) content, catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activity decrease and then increase. The germination potential, germination index, germination rate, seed germination vigor index, root length, root fresh weight, MDA and Pro content, and CAT activity of the Hongtianhu 101 seeds are higher than those of Xinxiang 8 for all salt concentrations employed here. However, hypocotyl length, fresh weight aboveground, and relative salt rate are lower in Hongtianhu 101 than in Xinxiang 8. The comprehensive evaluation of salt tolerance reveals that the total weighted values of the two membership function indexes increase first and then decrease as the mixed salt concentration increases. Compared with 5 g/L, which has the highest membership function value, the index under salt concentrations of 3 g/L, 10 g/L, and 15 g/L decreases by 4.7%-11.1%, 25.3%-28.3%, and 41.4%-45.1%, respectively. This study provides theoretical guidance for the breeding of salt-tolerant varieties of pepper and an analysis of the physiological mechanisms involved in salt tolerance and salt-tolerant cultivation.

【Objective】The study was carried out to explore the effects of different concentrations of uniconazole in plug media on the growth and development of different varieties of lettuce seedlings.【Method】Five lettuce varieties in southern China were used to study the effects of different concentrations (0-50 mg/L) of uniconazole on seedling growth, leaf shape parameters and soluble solids (TSS) of lettuce.【Result】With the increase of uniconazole concentration, the root fresh weight, root dry weight, shoot fresh weight and shoot dry weight of seedlings of various lettuce varieties increased first and then decreased. The root fresh weight and dry weight of bolting-tolerant lettuce and Roman upright lettuce were the highest under 10 mg/L uniconazole treatment, and those of other varieties were the highest under 5 mg/L uniconazole treatment. The total leaf width, maximum functional leaf width and total leaf area of seedlings also reached the maximum under 5 mg/L uniconazole treatment. The total leaf width and total leaf area of butter lettuce seedlings were larger than those of other varieties. The root-shoot ratio of iceberg lettuce, butter lettuce and bolting-tolerant lettuce increased with the increase of uniconazole concentration, while the root-shoot ratio of Hong Kong soft-tail lettuce and Roman upright lettuce increased first and then decreased. In addition, under the treatment of 50 mg/L uniconazole, SPAD values of lettuce seedlings of all varieties increased significantly, while plant height, total leaf area and TSS accumulation were severely inhibited.【Conclusion】Strong seedlings of lettuce could be cultivated by the medium with suitable concentration (5 mg/L) of uniconazole. The growth and development of lettuce seedlings would be inhibited by higher concentration of uniconazole.

为探究江西省赣州设施菜地土壤全硒(Se)的含量及其分布特征,于2021年对赣南地区设施蔬菜大棚采集0～20 cm耕层土壤样235件,测定了土壤采样点的经纬度、海拔及土壤中全硒含量和理化性质.结果表明,赣南地区设施菜地土壤全硒质量分数平均为0.31 mg/kg,变化范围为0.03～1.25 mg/kg,全硒含量分布频率符合正态分布.研究区域设施菜地富硒土壤资源较为丰富,85.1％的样点数土壤全硒含量处于足硒及以上水平(>0.175 mg/kg),其中有22.1％的样点数土壤属于富硒水平标准(>0.400～3.000 mg/kg),而富硒土壤主要集中在赣南地区的正西部及东北部等部分区域;7.2％和7.7％的样点数土壤全硒质量分数分别达硒不足(>0.125～0.175 mg/kg)和潜在硒不足水平(≤0.125 mg/kg),二者主要集中在赣南地区西南角部分区域,不存在硒中毒区域.海拔每增加1 m,设施土壤全硒质量分数降低5.35×10-4 mg/kg;纬度每增加1°和pH值每增加一个单位,土壤全硒质量分数分别增加0.090和0.049 mg/kg.综上,赣南地区设施菜地土壤硒资源具有较大利用潜力,并可依据研究区域全硒含量分布特征开展具有针对性的设施富硒蔬菜发展策略.

以5种生菜为试材,使用穴盘基质拌施多效唑育苗来模拟土壤多效唑残留的方法,其中多效唑浓度(以有效成分计)设置A1(0 mg·L-1)、A2(2.5 mg·L-1)、A3(5.0 mg·L-1)、A4(10.0 mg·L-1)、A5(20.0 mg·L-1)、A6(40.0 mg·L-1)和A7(80.0mg·L-1)共7种残留水平,研究了多效唑残留对生菜幼苗质量、叶型及地上部可溶性固形物含量的影响,以期探明生菜育苗生长对多效唑残留浓度的响应机制.结果表明:随多效唑浓度增加,各生菜株高、地上部鲜质量、地上部干质量、总叶面积、总叶长、总叶宽、最大功能叶叶长、最大功能叶叶宽及可溶性固形物均降低,SPAD值及根冠比均增加,而根鲜质量及根干质量先增后降.其中A5、A6和A7处理株高、地上部鲜质量、地上部干质量、总叶面积及可溶性固形物等指标均显著低于A1处理,SPAD值和根冠比等指标却均显著高于A1处理.随菜地多效唑残留浓度增加,各生菜苗期生长发育受抑制程度增加,其中多效唑残留浓度为A5(20 mg·L-1)及其以上时其抑制效果均达显著水平,对生菜育苗质量极为不利.

为明确南方晚粳稻适宜的氮肥运筹,设计3个不同施氮水平,分别为N210(210 kg/hm2)、N255(255 kg/hm2)及N300(300 kg/hm2),基肥、分蘖肥、穗肥的施氮比例为5∶2∶3,并在N255施氮水平下设置4种不同基肥、分蘖肥、穗肥的施氮比例,分别为BR6(6∶2∶2)、BR5 (5∶2∶3)、BR4(4∶2∶4)及BR3 (3∶2∶5),研究氮肥运筹对晚粳稻产量、干物质生产及氮素利用率的影响.结果 表明,随施氮量增加,晚粳稻产量先增后降,与N255处理相比,N300及N210处理分别降低1.8％～2.0％和6.0％～7.2％.随施氮量增加,晚粳稻氮素总积累量增加,抽穗至成熟期氮素积累量及该阶段占总氮素积累量的比例、氮素偏生产力及氮素收获指数均降低.随基肥施氮比例降低,晚粳稻产量、氮素偏生产力及氮素收获指数均先增后降,镇稻11号和甬优2640分别在BR5和BR4处理时最高,但两品种在这2个处理间的差异均不显著.随基肥施氮比例降低,晚粳稻成熟期氮素积累量、抽穗期至成熟期氮素积累量及该阶段积累量占总积累量的比例均增加.在江西等双季稻区,建议施氮量以255 kg/hm2,基肥、蘖肥、穗肥的施氮比例以(5∶2∶3)～(4∶2∶4)为宜,具体因品种特性而异.

为改善脐橙汁的稳定性和品质,通过单因素试验研究了均质压力、进料温度、均质次数对脐橙汁悬浮稳定性、离心沉淀率、黏度及Vc和总黄酮含量的影响,结果表明:随着均质压力(10～60MPa)的增加、进料温度和均质次数的上升,离心沉淀率下降,悬浮稳定性上升.适当的均质压力(10～40 MPa)可增加总黄酮含量,但对Vc含量并无显著影响;对于进料温度,从室温～40℃之间Vc无显著变化,黄酮含量显著上升,40℃之后Vc含量有所增加,黄酮含量显著下降;随着均质次数的增加,Vc和黄酮含量均下降.以离心沉淀率、悬浮稳定性、黏度为评价指标,通过正交试验最终确定最佳均质条件为:均质压力40MPa、均质次数2次、进料温度60℃.

[目的]南丰蜜桔作为江西省四大特色柑桔产业之一,加快南丰蜜桔品质提升对促进江西柑桔产业高质量发展具有重要作用.2007年笔者发现一棵(4年树龄)砧木为枳、接穗来源于南丰蜜桔"杨小2-6"的芽变优株,并经连续10余年高接鉴定表明该变异品种遗传稳定性较好,品质及耐贮特性也较佳,该变异优株被命名为"南丰蜜桔芽变优株ZZL-03".为评价南丰蜜桔芽变优株"ZZL-03"(突变体)果实采后品质变化特征,客观探讨其商品性.[方法]以普通南丰蜜桔为对照,采收后每隔10 d测定其果实耐贮特性、内在品质及果皮果汁的色差指数等指标,并于采摘期对果实外在品质进行测定.[结果]研究表明,随贮藏期延长(采后4～34 d内),突变体及对照组的果实硬度、可滴定酸、果皮L、h0值均逐渐降低,果实可溶性固形物含量、腐烂率、浮皮率、可溶性糖、糖酸比、固酸比、果皮a、c值及果汁L、a、b、c值均逐渐增加,而维生素C、果皮b值及果汁h0值均先增后降.在贮藏各时期,突变体果实硬度、可溶性固形物含量、可溶性糖、糖酸比、固酸比和维生素C均显著高于对照(P<0.05),分别平均高48.7％、53.7％、35.2％、66.9％、89.9％和25.3％;而腐烂率、浮皮率、可滴定酸均显著低于对照,平均低于45.0％、71.0％和18.9％.突变体果皮及果汁L、a、b及c值均高于对照,但h0值有所降低.突变体果实皮薄而硬,外在品质显著优于对照.[结论]综上,与对照相比突变体果实采后具有更好的耐贮特性及果实品质,研究得出的贮藏期品质的变化规律可为蜜桔采后加工利用提供理论指导.

[目的]增施氮肥是实现水稻高产最为重要的措施之一,但过量施用氮肥会降低氮肥吸收利用率并造成氮素面源污染.合理的每穴苗数通过调节稻田基本苗数构建高产群体起点,但通过增加每穴苗数降低施氮量能否同步实现水稻高产及氮素高效利用目前还不清楚.旨在探索每穴苗数及氮肥用量对构建晚籼稻高产氮高效群体的协同调控效果.[方法]于2017—2018年,选用五优308及天优华占为晚籼稻材料,设CK(每穴2苗和N 180 kg/hm2)、T1(每穴3苗和N 144 kg/hm2)及T2(每穴4苗和N 126 kg/hm2)等3个处理,测定了水稻干物质生产、叶面积指数、产量及氮素吸收利用.[结果]随着增苗减氮调控程度增加,两品种产量均先增后降.与CK处理相比,五优308及天优华占品种T1处理产量分别增加0.36％～0.38％及8.73％～10.01％,其中天优华占T1处理与CK处理产量间差异达显著水平;天优华占T2处理产量增加0.95％～1.72％,而五优308品种T2处理产量却显著降低7.46％～7.96％.增苗减氮促进晚籼稻有效穗数增加,每穗粒数降低,结实率先增后降,千粒质量无显著变化.两品种抽穗期及成熟期的叶面积指数及幼穗分化期至成熟期的光合势均先增后降,五优308作物生长速率、总干物质量降低,而天优华占作物生长速率、总干物质量却均先增后降.总吸氮量降低,氮素偏生产力增加、氮素吸收利用率、生理利用率及农学利用率均先增后降.[结论]T1处理可同步协调"增苗"与"减氮"二者关系,可有效构建晚籼稻高产氮高效群体,但具体调控效果因品种而异.

作物秸秆含有丰富的磷、钾等营养元素,但秸秆还田下晚粳稻最佳磷钾配施目前尚不明确.采用磷钾两因素完全随机试验设计,设磷(P2O5)0,63.75,127.50,191.25 kg/hm2(记P0、P1、P2、P3)和钾(K2O)0,102,204,306 kg/hm2(记K0、K1、K2、K3)各4个水平.在水稻成熟期取样测定产量、品质及精米氮素累积量.结果表明:磷肥和钾肥均显著提高了晚粳稻产量、干物质量和收获指数,且二者具有显著互作效应;磷钾合理配施可协同促进晚粳稻产量,当磷、钾肥用量分别62.45 kg/hm2和206.08 kg/hm2时实现较高产.同时,适宜磷钾配施也显著协同提高精米氮素累积量.磷钾合理配施能够提高稻米出糙率、精米率、整精米率及胶稠度,但增加了垩白粒率、垩白度、直链淀粉及粗蛋白含量.除峰值黏度、热浆黏度及冷胶黏度在钾肥用量上存在显著性差异外,各RVA谱特征值在钾肥、磷肥及二者互作上均无显著性差异;其中增施钾肥峰值黏度、热浆黏度及冷胶黏度均先增后降.南方晚粳稻实际生产中应重视优化磷钾配施比例,在土壤地力中上等及秸秆全量还田条件下,采用P1K2的施肥方案可充分发挥磷钾的协同促进效应,同步实现晚粳稻高产、高效并兼顾优质生产.

为探究南方稻区优质晚粳稻适宜的断水及收获时期,2014～2015年以常规粳稻镇稻11号及籼粳杂交稻甬优2640为材料,探讨了不同断水时间(抽穗后28、35、42、49 d)、不同收获时期(抽穗后35、40、45、50、55 d)对晚粳稻籽粒充实度、产量及品质的影响.结果表明:在本试验条件下,每延迟1 d断水,镇稻11号及甬优2640产量分别增加21～23 kg/hm2及31～35 kg/hm2;每延迟1 d收获,两个品种产量分别增加63～66 kg/hm2及102～104 kg/hm2.断水(或收获)时期延迟,晚粳稻出糙率、精米率及整精米率增加,垩白粒率及垩白度降低,胶稠度及直链淀粉含量增加.抽穗后42～49 d断水或抽穗后50～55 d收获,晚粳稻产量及千粒重差异均不显著,稻米品质也差异不显著.可见,在江西中部稻区,晚粳稻抽穗后42～49 d断水及抽穗后50～55 d收获较适宜.