设施农业环境工程双语教学改革与实践

为了使设施农业环境工程双语教学满足新时期研究生培养国际化要求,结合课堂组织形式、教学模式创新、教学素材完善、教师队伍建设、双语教学课程网站建设、课程考核新模式进行探索与实践,建设了行之有效的双语教学质量保证体系,加强了对设施农业环境工程双语教学的组织实施,双语教学质量显著提高。

Light regulation of horticultural crop nutrient uptake and utilization

Plants demonstrate dynamic changes in molecular structures under fluctuating light conditions.Accumulating evidence suggests that light plays a vital role in plant growth and morphogenesis.In particular,light has a role in the absorption and utilization of nutrients in plants.Despite significant progress in understanding the mechanism of nutrient acquisition and assimilation,how light affects and regulates ion uptake remains a question.Studies in model plants,Arabidopsis thaliana,suggest that light affects the nutrient utilization in roots through a complex regulatory network;nonetheless,the molecular mechanisms underlying the various effects of light on these processes in crop plants remain fragmentary.In this review,we discuss the light effects(light quality,light intensity,and photoperiod)on nutrient uptake and utilization in horticultural crops for optimizing crop productivity and increasing fertilizer use efficiency.

Methyl jasmonate mediates melatonin-induced cold tolerance of grafted watermelon plants

Root–shoot communication has a critical role in plant adaptation to environmental stress.Grafting is widely applied to enhance the abiotic stress tolerance of many horticultural crop species;however,the signal transduction mechanism involved in this tolerance remains unknown.Here,we show that pumpkin-or figleaf gourd rootstock-enhanced cold tolerance of watermelon shoots is accompanied by increases in the accumulation of melatonin,methyl jasmonate(MeJA),and hydrogen peroxide(H_(2)O_(2)).Increased melatonin levels in leaves were associated with both increased melatonin in rootstocks and MeJA-induced melatonin biosynthesis in leaves of plants under cold stress.Exogenous melatonin increased the accumulation of MeJA and H_(2)O_(2) and enhanced cold tolerance,while inhibition of melatonin accumulation attenuated rootstock-induced MeJA and H_(2)O_(2) accumulation and cold tolerance.MeJA application induced H_(2)O_(2) accumulation and cold tolerance,but inhibition of JA biosynthesis abolished rootstock-or melatonin-induced H_(2)O_(2) accumulation and cold tolerance.Additionally,inhibition of H_(2)O_(2) production attenuated MeJA-induced tolerance to cold stress.Taken together,our results suggest that melatonin is involved in grafting-induced cold tolerance by inducing the accumulation of MeJA and H_(2)O_(2).MeJA subsequently increases melatonin accumulation,forming a self-amplifying feedback loop that leads to increased H_(2)O_(2) accumulation and cold tolerance.This study reveals a novel regulatory mechanism of rootstock-induced cold tolerance.

Light quality regulates plant biomass and fruit quality through a photoreceptor-dependent HY5-LHC/CYCB module in tomato

Increasing photosynthesis and light capture offers possibilities for improving crop yield and provides a sustainable way to meet the increasing global demand for food.However,the poor light transmittance of transparent plastic films and shade avoidance at high planting density seriously reduce photosynthesis and alter fruit quality in vegetable crops,and therefore it is important to investigate the mechanisms of light signaling regulation of photosynthesis and metabolism in tomato(Solanum lycopersicum).Here,a combination of red,blue,and white(R1W1B0.5)light promoted the accumulation of chlorophyll,carotenoid,and anthocyanin,and enhanced photosynthesis and electron transport rates by increasing the density of active reaction centers and the expression of the genes LIGHT-HARVESTING COMPLEX B(SlLHCB)and A(SlLHCA),resulting in increased plant biomass.In addition,R1W1B0.5 light induced carotenoid accumulation and fruit ripening by decreasing the expression of LYCOPENEβ-CYCLASE(SlCYCB).Disruption of SlCYCB largely induced fruit lycopene accumulation,and reduced chlorophyll content and photosynthesis in leaves under red,blue,and white light.Molecular studies showed that ELONGATED HYPOCOTYL 5(SlHY5)directly activated SlCYCB,SlLHCB,and SlLHCA expression to enhance chlorophyll accumulation and photosynthesis.Furthermore,R1W1B0.5 light-induced chlorophyll accumulation,photosynthesis,and SlHY5 expression were largely decreased in the slphyb1cry1 mutant.Collectively,R1W1B0.5 light noticeably promoted photosynthesis,biomass,and fruit quality through the photoreceptor(SlPHYB1 and SlCRY1)-SlHY5-SlLHCA/B/SlCYCB module in tomato.Thus,the manipulation of light environments in protected agriculture is a crucial tool to regulate the two vital agronomic traits related to crop production efficiency and fruit nutritional quality in tomato.

Effects of Hypoxia Stress and Different Level of Mn2+ on Antioxidant Enzyme of Tomato Seedlings

The changes of antioxidant enzyme activities and related genes expression of tomato seedlings were evaluated under hypoxia stress with different levels of Mn2+. Activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxide (APX), glutathione reductase (GR), catalase (CAT), the contents of H2O2, ascorbic (AsA) and malondialdehyde (MDA) were studied to investigate how active oxygen damaged the membrane lipid under hypoxia stress. With 10-200 μmol?L-1 Mn2+, the activities of SOD, POD, APX, GR and the contents of H2O2, AsA, MDA of leaves and roots increased significantly, which indicated that low Mn2+ could eliminate the active oxygen and protect the membrane lipid from hurt. But the activities of catalase (CAT) decreased evidently in the root. When the concentration of Mn2+ reached 400-600 μmol?L-1 under hypoxia stress, the activities of SOD, POD, APX, GR and ASA content decreased remarkably. However, the contents of H2O2 and MDA increased contrarily. A series of resistance genes level achieved peak value with 10 μmol?L-1 Mn2+. The expression level of SOD, CAT, APX, POD, GR were 6.28, 2.19, 5.66, 5.21 and 6.79 times compared to control respectively. These results illustrated appropriate amount of Mn2+ could reduce the damage of active oxygen under hypoxia stress, but reversely, high level of Mn2+ just aggravated the already serious damage to the tomato seedlings.

Effects of arbuscular mycorrhizal fungi,biochar,selenium,silica gel,and sulfur on arsenic uptake and biomass growth in Pisum sativum L.

Arsenic(As)is carcinogenic and highly toxic to plants.Crops accumulate As when grown in field soils irrigated with As-contaminated groundwater.The accumulation of As in roots,shoots,and grains of pea varieties can negatively affect human health via the food chain.This research is focused on the biomass growth and alleviation of As accumulation in roots,shoots,and grains of pea varieties in high As soil amended with arbuscular mycorrhizal fungi(AMF),biochar(BC),selenium(Se),silica gel(Si-gel),and sulfur(S).Root,shoot,and grain masses were found higher in pea grown in As soil amended with AMF,Se,Si-gel,and S.Amendments with rice husk and sawdust BC was found less effective to increase growth parameters in Bangladesh Agricultural Research Institute(BARI)Motor 2.Arsenic in grains was reduced by 77%,71%,and 69%by AMF,Se,and Si-gel,respectively.It is recommended that soil amendments with AMF,S,and Se have great potential for improving biomass production of pea grown in As-contaminated soil,as well as reducing As transfer to humans through the food chains.