Guohui Xu, Lei Lei, and Hexin Wang
Guohui Xu, Lei Lei, Hexin Wang, and Xin Lou
Feng-yang Yu, Yue-e Xiao, Lin Cheng, Shu-cheng Feng, and Lei-lei Zhang
Ting Lei, Yang Song, Xuehua Jin, Tianyu Su, and Yiwen Pu
The plant Zantedeschia hybrida is colorful and suitable for cut flowers and potted plants. This study employed a colorimetric method for the determination of spathe color phenotypes in 27 Z. hybrida cultivars and classified them into six major color classes. To characterize the coloration mechanism of the Z. hybrida spathe, this study explored the main colorants and pigment distribution using high-performance liquid chromatography (HPLC) with photodiode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS), ultra-performance liquid chromatography/hybrid triple quadrupole linear ion trap mass spectrometry (UPLC-Q-TRAP-MS), and tissue sections. The results showed that flavonoids were colorants in the spathes of different color groups and that cyanidin (Cy) was the main colorant, whereas carotenoids were not detected in the spathe. Total anthocyanin (TA) content was negatively correlated with lightness (L*) of coloration, such that a spathe with a higher TA and thicker pigmented cell layer showed a deeper color; however, there was no correlation between deep coloration in a spathe and flattened upper epidermal cells. The difference in TA was the main reason for the color variation among Z. hybrida of different color groups, whereas the total flavones and flavonols (TF) played a key role in the coloration of the orange and yellow group.
Lei Jiajun, Li Yuhua, Du Guodong, Dai Hanping, and Deng Mingqin
A natural strawberry genotype, `Jilin 4', was collected from the Changbai Mountains located in Gongzhuling Region, Jilin Province, Northeast China. It was identified as a pentaploid (2n = 5x = 35) by counting the chromosomes of the root-tip cells. Natural pentaploid strawberries have not been reported as originating in China or outside of California in the U.S. Jilin 4 was the most vigorous genotype among representatives of all 15 wild species of Fragaria and more than 60 cultivars of F. ×ananassa in a common garden. The size of its flowers and anthers were similar to those of cultivars and it produced abundant runners. The pollen was viable, but the pistils were sterile. It appeared to be drought and cold tolerant, but showed symptoms of local virus infection. There are three possible origins of Jilin 4, which are discussed in this report.
Yongqiang Qian, Deying Li, Lei Han, and Zhenyuan Sun
Understanding the effect of photosynthate translocation on the shoot density of buffalograss (Buchloe dactyloides) is very important to improve its turf quality. The objective of this study was to examine the effects of water stress on water transport patterns, endogenous hormone distribution and allocation, and photosynthate allocation for connected buffalograss ramets. Clones from a single parent plant of ‘Texoka’ buffalograss were used to generate three-ramet units. Ramets are members of a clone that are not independent from the parent plant. Each water stress treatment had one of the three ramets cultured in half-strength Hoagland solution with 30% of polyethylene glycol (PEG) of −1.2 MPa ψS, while the other two ramets were kept in half-strength Hoagland solution with ψS of −0.05 MPa. Results indicated that inter-ramet water integration happened when one of the connected ramets was under water stress. Transzeatin riboside content decreased in roots treated with PEG. Abscisic acid content increased in the roots of all treatments compared with the control. Water stress caused a reduction of indole-3-acetic acid content in shoots and roots, especially the ramet stressed. Gibberellic acid content in shoots and roots of all treatments increased compared with the control. Within the control, young ramets were sinks of photosynthate, but translocation toward older ramets was detected using 14CO2 label when the older ramet was under stress. Xylem, phloem, and parenchyma cells were probably involved in the physiological integration of these responses. Fates of connected clonal ramets of buffalograss were interrelated and the agronomic significance of this result should be evaluated further.
Chih-Hsien Lei, Jon T. Lindstrom, and William R. Woodson
At anthesis, petunia pollen contains large amounts of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). This ACC is thought to contribute to the rapid burst of ethylene produced by the pistil following pollination. An analysis of ACC content in developing anthers revealed that ACC began to accumulate the day before anthesis, indicating its synthesis was a late event in pollen development. We employed degenerate DNA primers to conserved amino acid sequences of ACC synthesis to amplify a cDNA from anther mRNA by RT-PCR. The resulting cDNA (pACS2) was sequenced and found to represent ACC synthase. Use of pACS2 as a hybridization probe revealed an increase in ACC synthase mRNA concomitant with the increase in ACC content. Further analysis indicated the ACC synthase mRNA was localized specifically to the haploid pollen grain. In an attempt to determine the function of ACC in pollen maturation or pollen–pistil interactions, we have generated a series of transgenic petunias designed to inhibit the accumulation of ACC in pollen. For these experiments, we have employed a pollen-specific promoter (LAT52) from tomato to drive the expression of antisense pACS2 or the coding region of ACC deaminase. The results of the experiments will be discussed.
Jon T. Lindstrom, Chih-Hsien Lei, and William R. Woodson
Petunia hybrida pollen accumulates significant levels of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) late in development. This pollen ACC is thought to play a role in the rapid burst of ethylene produced by pollinated pistils. To investigate this further, we have expressed the ACC deaminase gene product from Pseudomonas in transgenic petunias under the control of three different promoters including CaMV-35S, LAT52, and TA29 directing construction expression, pollen-specific expression and tapetum-specific expression, respectively. Several transgenic plants expressing the LAT52-ACC deaminase gene exhibited significant reduction of ACC in pollen. Two independent transformants contained only trace amounts of ACC in pollen. In contrast, the other promoters did not lead to reduced ACC in pollen. Pollination of wild-type pistils with pollen from LAT52-ACC deaminase plants elicited increased ethylene similar to wild-type pollen. Fecundity was unaffected by the reduction in pollen ACC content. Taken together, we conclude pollen-borne ACC is not the elicitor of pollination-induced ethylene production by pistils.
Lei Gao, Shengjie Zhao, Xuqiang Lu, Nan He, and Wenge Liu
Zhenghui Tang, Honghui Lin, Lei Shi, and Weilun Chen
Experiments were conducted to establish an efficient protocol for micropropagation of Chirita longgangensis W.T. Wang. Somatic embryos formed directly at the cut edges of C. longgangensis leaf explants on Murashige and Skoog (MS) medium supplemented with benzylaminopurine (BA) and α-naphthalene acetic acid (NAA). During the somatic embryo induction stage, leaf explants and basal leaf explants were used. Leaves were more appropriate explants than the basal leaf explants. The best medium was modified MS macronutrients and micronutrients supplemented with 0.5 mg·L−1 BA and 0.1 mg·L−1 NAA (the best mean number of somatic embryos per explants was 24.10 ± 1.63). The second stage was root induction and elongation. In vitro regenerated plantlets rooted best on MS medium containing 0.1 mg·L−1 indole-3-acetic acid (IAA) and 30 g·L−1 sucrose. Rooted plantlets, following acclimatization in a greenhouse, were successfully transferred to field conditions, and 95% of the plants survived. Application of this protocol has the ability for mass multiplication, in a limited time, of the endangered species C. longgangensis.