Germination characteristics of plump and shriveled seeds of Tamarix ramosissima matured in different seasons

Tamarix ramosissima has bi-seasonal flowering and fruiting. Although the basic germination characteristics of T. ramosissima seeds have been evaluated, there is a lack of information about the effects of seed plumpness on germination. Effects of seed plumpness and season of maturity and light conditions on germination were tested. Plump seeds matured in spring or summer had similar size and pappus length. The size of plump seeds was significantly larger than that of shriveled seeds. Both types of seeds matured in summer germinated better than seeds matured in spring. Germination percentage of plump seeds was significant higher than that of shriveled seeds, especially for seeds matured in spring. Darkness significantly decreased the germination of seeds matured in summer. This study provides comprehensive information about the seed germination requirements of T. ramosissima and the results can be used in restoration of desert lands.

EjRAV1/2 Delay Flowering Through Transcriptional Repression of EjFTs and EjSOC1s in Loquat

Most species in Rosaceae usually need to undergo several years of juvenile phase before the initiation of flowering. After 4–6 years’ juvenile phase, cultivated loquat (Eriobotrya japonica), a species in Rosaceae, enters the reproductive phase, blooms in the autumn and sets fruits during the winter. However, the mechanisms of the transition from a seedling to an adult tree remain obscure in loquat. The regulation networks controlling seasonal flowering are also largely unknown. Here, we report two RELATED TO ABI3 AND VP1 (RAV) homologs controlling juvenility and seasonal flowering in loquat. The expressions of EjRAV1/2 were relatively high during the juvenile or vegetative phase and low at the adult or reproductive phase. Overexpression of the two EjRAVs in Arabidopsis prolonged (about threefold) the juvenile period by repressing the expressions of flowering activator genes. Additionally, the transformed plants produced more lateral branches than the wild type plants. Molecular assays revealed that the nucleus localized EjRAVs could bind to the CAACA motif of the promoters of flower signal integrators, EjFT1/2, to repress their expression levels. These findings suggest that EjRAVs play critical roles in maintaining juvenility and repressing flower initiation in the early life cycle of loquat as well as in regulating seasonal flowering. Results from this study not only shed light on the control and maintenance of the juvenile phase, but also provided potential targets for manipulation of flowering time and accelerated breeding in loquat.

Biology Of Crocus Sativus L. In Termiz

This article observed the generative phase of the saffron plant grown in Termez conditions. Based on the data obtained, the daily and seasonal flowering dynamics of the plant were constructed.

A MADS-Box Gene CiMADS43 Is Involved in Citrus Flowering and Leaf Development through Interaction with CiAGL9

MADS-box genes are involved in various developmental processes including vegetative development, flower architecture, flowering, pollen formation, seed and fruit development. However, the function of most MADS-box genes and their regulation mechanism are still unclear in woody plants compared with model plants. In this study, a MADS-box gene (CiMADS43) was identified in citrus. Phylogenetic and sequence analysis showed that CiMADS43 is a GOA-like Bsister MADS-box gene. It was localized in the nucleus and as a transcriptional activator. Overexpression of CiMADS43 promoted early flowering and leaves curling in transgenic Arabidopsis. Besides, overexpression or knockout of CiMADS43 also showed leaf curl phenotype in citrus similar to that of CiMADS43 overexpressed in Arabidopsis. Protein–protein interaction found that a SEPALLATA (SEP)-like protein (CiAGL9) interacted with CiMADS43 protein. Interestingly, CiAGL9 also can bind to the CiMADS43 promoter and promote its transcription. Expression analysis also showed that these two genes were closely related to seasonal flowering and the development of the leaf in citrus. Our findings revealed the multifunctional roles of CiMADS43 in the vegetative and reproductive development of citrus. These results will facilitate our understanding of the evolution and molecular mechanisms of MADS-box genes in citrus.

Diversification in Functions and Expressions of Soybean FLOWERING LOCUS T Genes Fine-Tunes Seasonal Flowering

The proper timing of flowering in response to environmental changes is critical for ensuring crop yields. FLOWERING LOCUS T (FT) homologs of the phosphatidylethanolamine-binding protein family play important roles as floral integrators in many crops. In soybean, we identified 17 genes of this family, and characterized biological functions in flowering for ten FT homologs. Overexpression of GmFT homologs in Arabidopsis revealed that a set of GmFT homologs, including GmFT2a/2b, GmFT3a/3b, and GmFT5a/5b, promoted flowering similar to FT; in contrast, GmFT1a/1b, GmFT4, and GmFT6 delayed flowering. Consistently, expressions of GmFT2a, GmFT2b, and GmFT5a were induced in soybean leaves in response to floral inductive short days, whereas expressions of GmFT1a and GmFT4 were induced in response to long days. Exon swapping analysis between floral activator GmFT2a and floral repressor GmFT4 revealed that the segment B region in the fourth exon is critical for their antagonistic functions. Finally, expression analysis of GmFT2a, GmFT5a, and GmFT4 in soybean accessions exhibiting various flowering times indicated that the mRNA levels of GmFT2a and GmFT5a were higher in early flowering accessions than in late-flowering accessions, while GmFT4 showed the opposite pattern. Moreover, the relative mRNA levels between GmFT2a/GmFT5a and GmFT4 was important in determining day length-dependent flowering in soybean accessions. Taken together, our results suggest that the functions of GmFT homologs have diversified into floral activators and floral repressors during soybean evolution, and the timing of flowering in response to changing day length is determined by modulating the activities of antagonistic GmFT homologs.

A metabolic coincidence mechanism controls winter photoperiodism in plants

Plants have served as a preeminent study system for photoperiodism because of their propensity to flower in concordance with the seasons. A nearly singular focus on understanding seasonal flowering has been to the detriment of discovering other photoperiod measuring mechanisms that may be necessary for vegetative health. Here we use bioinformatics to identify a group of winter photoperiod-induced genes in Arabidopsis and show that one, PP2-A13, is critical for fitness and survival, exclusively in winter-like photoperiods. We create a real-time photoperiod reporter, using the PP2-A13 promoter driving luciferase, and show that winter photoperiod genes are regulated independent of the canonical CO/FT mechanism for photoperiodic flowering. The reporter then allows us to identify the first genetic and cellular drivers of winter photoperiodism and reveal a mechanism that relies on coincidence between light capture through photosynthesis and rhythmic metabolism. This work demonstrates that plants have distinct photoperiod measuring mechanisms that enact critical biological and developmental processes in different seasons.

Complementary Effects of Agricultural Tourism and Tourist Destination Brands in Preserved Scenic Areas in Mountain Areas of China and Europe

Many scenic areas in mountain regions have attained preservation status, which enhances strategies to attract tourists based on its unique natural or cultural resources and its original brand. It is a particular challenge for plant-dependent assets how tourist attraction for the scenic areas could be increased in the off-season, taking account of the strong seasonal fluctuations. The paper focuses on lessons from a specific case of preserved scenic area, the area of rhododendron (“Dujuan” in Chinese) and compares it with several European examples. As indicated in the denomination of “Baili Dujuan” Scenic Area, a National Park in Guizhou Province in China, this plant is the leading asset in that area. The characteristics of the seasonal flowering of rhododendrons causes Baili Dujuan serious problems of a seasonal tourist offer. For several years Baili Dujuan has been promoting complementary activities of agricultural tourism and developing a brand of flower-enjoying destinations, by supporting the local farmers to grow also other economic flowers and fruit trees that bloom in different seasons. Such instruments have contributed to extend the flow of tourists for longer periods of the year, generating also substantial benefits to farmers and other local industries. Based on the emerging initiatives in Baili Dujuan and interesting experiences from protected mountain areas in Europe, the complementary effects of agritourism and tourist destination brands in Preserved Scenic Areas will be explored for further development.