Introduction Performance and Application Evaluation of Leafy Ornamental Vegetables in Kunming City

[Objectives]This study was conducted to enrich the plant resource of ornamental vegetables in Kunming. [Methods]15 leafy vegetables were selected as test materials in this study. This study investigated the biological characteristics of the 15 ornamental vegetables by introduction trial and grey correlation analysis. In addition,we discussed the application of ornamental vegetables in urban agriculture. [Results]The grey correlation values of 11 ornamental vegetables were greater than 0. 6. The grey correlation values of other four ornamental vegetables were less than 0. 5. Among them,the grey correlation of Beta vulgaris L. var. cicla L. was 0. 94,which have the highest appreciation evaluation. The second appreciation evaluation belonged to rainbow leafy Beta vulgaris L. var. cicla L. with grey correlation of 0. 88. [Conclusions] In short,there are nine ornamental vegetables could be applied in the urban agriculture of Kunming,and there are six ornamental vegetables must be further investigated by cultivation experiment,to understand their cultivation characteristics and key points of management.

Microclimate control to increase productivity and nutritional quality of leafy vegetables in a cost-effective manner

Food security is one of the key global challenges in this century.In Singapore,our research team has been using novel aeroponic technology to produce fresh vegetables since 1997.Aeroponic systems allow for year-round production of not only tropical,but also sub-tropical and temperate fresh vegetables,by simply cooling the roots suspended in aeroponic systems while the aerial parts grow under tropical ambient environments.It has also been used to investigate the impacts of root-zone CO_(2)on vegetables by enriching root-zone CO_(2)while their aerial portions were subjected to constant atmospheric CO_(2).To compensate for the lack of available land,Singapore also needs to develop a farming system that can increase productivity per unit land area by many-fold.Over the past 10 years,my research team has established a commercially viable LED integrated vertical aeroponic farming system to grow different leafy vegetables under different LED spectra,intensities,and durations in the tropical greenhouse.The results demonstrate that it is possible to increase shoot production and rate of shoot production of leafy vegetables by increasing light intensity and extending the photoperiod under effective LED lighting.Furthermore,temperate vegetable crops such as lettuce were able to acclimate to high light intensity under supplementary LED lights to natural sunlight in the greenhouse.Supplementary LED lightings promote both leaf initiation and expansion with increased photosynthetic pigments,higher Cyt b6f and Rubisco protein contents on a per area basis and thus improve photosynthetic capacity and enhance productivity.Plants sense and respond to changes in their immediate environments(microclimate),manipulating the root zone temperature(RZT)and water supply will impact not only their growth and development but also their nutritional quality.Our on-going research aims to investigate if the nutritional quality of leafy vegetables could be improved under suboptimal RZT and mild water deficit through deficit irrigation.If substantial energy and water savings in urban farming can be achieved without substantial yield penalty but with higher nutritional quality,the amount of water and energy saved can bring substantial benefits to society.

Overexpression of ACL 1 （abaxially curled leaf 1） Increased Bulliform Cells and Induced Abaxial Curling of Leaf Blades in Rice

Understanding the genetic mechanism underlying rice leaf-shape development is crucial for optimizing rice configuration and achieving high yields; however, little is known about leaf abaxial curling. We isolated a rice transferred DNA （T-DNA） insertion mutant, BY240, which exhibited an abaxial leaf curling phenotype that co-segregated with the inserted T-DNA. The T-DNA was inserted in the promoter of a novel gene, ACL1 （Abaxially Curled Leaf 1）, and led to overexpression of this gene in BY240. Overexpression of ACL1 in wild-type rice also resulted in abaxial leaf curling. ACL1 encodes a protein of 116 amino acids with no known conserved functional domains. Overexpression of ACL2, the only homolog of ACL1 in rice, also induced abaxial leaf curling. RT-PCR analysis revealed high expressions of ACLs in leaf sheaths and leaf blades, suggesting a role for these genes in leaf development. In situ hybridization revealed non-tissue-specific expression of the ACLs in the shoot apical meristem, leaf primordium, and young leaf. Histological analysis showed increased number and exaggeration of bulliform cells and expansion of epidermal cells in the leaves of BY240, which caused developmental discoordination of the abaxial and adaxial sides, resulting in abaxially curled leaves. These results revealed an important mechanism in rice leaf development and provided the genetic basis for agricultural improvement.

Histone Acetyltransferase AtGCN5/HAG1 Is a Versatile Regulator of Developmental and Inducible Gene Expression in Arabidopsis

Histone acetylation/deacetylation is a dynamic process and plays an important role in gene regulation. Histone acetylation homeostasis is regulated by antagonist actions of histone acetyltransferases （HAT） and deacetylases （HDAC）. Plant genome encodes multiple HATs and HDACs. The Arabidopsis HAT gene AtGCNS/HAGlplays an essential role in many plant development processes, such as meristem function, cell differentiation, leaf and floral organogenesis, and responses to environmental conditions such as light and cold, indicating an important role of this HAT in the regulation of both long-term developmental switches and short-term inducible gene expression. AtGCN5 targets to a large number of promoters and is required for acetylation of several histone H3 lysine residues. Recruitment of AtGCN5 to target promoters is likely to be mediated by direct or indirect interaction with DNA-binding transcription factors and/or by interaction with acetylated histone lysine residues on the targets. Interplay between AtGCN5 and other HATand HDAC is demonstrated to control specific regulatory pathways. Analysis of the role of AtGCN5 in light-inducible gene expression suggests a function of AtGCN5 in preparing chromatin commitment for priming inducible gene activation in plants.

Kinesin-4 Functions in Vesicular Transport on Cortical Microtubules and Regulates Cell Wall Mechanics during Cell Elongation in Plants

In plants, anisotropic cell expansion depends on cortical microtubules that serve as tracks along which macromolecules and vesicles are transported by the motor kinesins of unknown identities. We used cotton （Gossypium hirsutum） fibers that underwent robust elongation to discover kinesins that are involved in cell elongation and found Gh KINESIN-4A expressed abundantly. The motor was detected by immunofluores- cence on vesicle-like structures that were associated with cortical microtubules. In Arabidopsis thaliana, the orthologous motor At KINESIN-4A/FRA1, previously implicated in cellulose deposition during second- ary growth in fiber cells, was examined by live-cell imaging in cells expressing the fluorescently tagged functional protein. The motor decorated vesicle-like particles that exhibit a linear movement along cortical microtubules with an average velocity of 0.89 l^m/min, which was significantly different from those linked to cellulose biosynthesis. We also discovered that At KINESIN-4A/FRA1 and the related At KINESIN-4C play redundant roles in cell wall mechanics, cell elongation, and the axial growth of various vegetative and reproductive organs, as the loss of At KINESIN-4C greatly enhanced the defects caused by a null mutation at the KINESIN-4A/FRA 1 locus. The double mutant displayed a lack of cell wall softening at normal stages of rapid cell elongation. Furthermore, enhanced deposition of arabinose-containing carbohydrate was detected in the kinesin-4 mutants. Our findings established a connection between the Kinesin-4-based transport of cargoes containing non-cellulosic components along cortical microtubules and cell wall mechanics and cell elongation in flowering plants.

Coordination of Plastid and Light Signaling Pathways upon Development of Arabidopsis Leaves under Various Photoperiods

Plants synchronize their cellular and physiological functions according to the photoperiod （the length of the light period） in the cycle of 24 h. Photoperiod adjusts several traits in the plant life cycle, including flowering and senes- cence in annuals and seasonal growth cessation in perennials. Photoperiodic development is controlled by the coordinated action of photoreceptors and the circadian clock. During the past 10 years, remarkable progress has been made in under- standing the molecular mechanism of the circadian clock, especially with regard to the transition of Arabidopsis from the vegetative growth to the reproductive phase. Besides flowering photoperiod also modifies plant photosynthetic struc- tures and traits. Light signals controlling biogenesis of chloroplasts and development of leaf photosynthetic structures are perceived both by photoreceptors and in chloroplasts. In this review, we provide evidence suggesting that the photope- riodic development of Arabidopsis leaves mimics the acclimation of plant to various light intensities. Furthermore, the chloroplast-to-nucleus retrograde signals that adjust acclimation to light intensity are proposed to contribute also to the signaling pathways that control photoperiodic acclimation of leaves.