The catabolism of fatty acid (FA) is regarded as a key pathway of aroma volatile compounds in oriental sweet melon (Cucumis melo var. makuwa). In our research, two cultivars of oriental sweet melon, Caihong7 and Tianbao, were employed to illuminate which step of the biosynthetic pathway of aroma compounds could be regulated by ethylene (ETH). The role of ETH in determining the profiles of straight-chain aroma volatile compounds, levels of FA as aroma precursors, activities of aroma-related enzymes derived from FA pathway, and expression patterns of key enzymes were investigated. Overall, exogenous application of ETH increased the production rates of endogenous ETH and levels of FA. Compared with control, the level of straight-chain esters, especially the acetate, hexanoate, and hexyl esters, was significantly increased by ETH, whereas the content of alcohol and aldehyde reduced. In addition, the metabolism of free FA included linoleic acid (LA), linolenic acid (LeA), and oleic acid (OA) appeared to be ETH-dependent. The activities of lipoxygenase (LOX), alcohol dehydrogenase (ADH), and alcohol acetyltransferase (AAT) as well as the expression patterns of Cm-ADH1, Cm-ADH2, Cm-AAT1, and Cm-AAT4 were positively regulated by ETH. In contrast, hydroperoxide lyase (HPL) and Cm-AAT2 and Cm-AAT3 seemed to be independent of ETH modulation. These results suggested that the dissimilation of FA included LA, LeA, and OA into the acetate, hexanoate, and hexyl esters mainly through ETH regulating the LOX pathway by enhancing the expression of particular members of aroma-related key enzyme gene families as well as the activities of dehydrogenation and esterification.
Yan Li, Hongyan Qi, Yazhong Jin, Xiaobin Tian, Linlin Sui and Yan Qiu
Lanqing Wang, Yinfeng Li, Dehai Liu, Chaohui Zhang, Yuancheng Qi, Yuqian Gao, Jinwen Shen and Liyou Qiu
We investigated a practical method for immobilizing liquid spawn of oyster mushroom (Pleurotus ostreatus) to prolong the storage time and provide convenient transportation of liquid spawn of edible mushrooms. The method was based on the mycelial pellets of liquid spawn adsorbed in carriers. Selected carriers were similar to cultivation substrates, and the best carrier was a mixture of cottonseed hull, corn core, and wheat bran with a ratio of 4.5:4.5:1 by weight. Immobilized spawn were prepared by mixing the pellets from liquid spawn with carriers using a ratio of 1:8 by weight. Within the first 15 days of storage at 20–25 °C, the immobilized spawn grew strongly, respiration intensity and cellulase activities rose rapidly, and the count and brightness of the isozyme bands of esterase, peroxidase, and polyphenol oxidase increased remarkably as well. From days 30 to 60, the cellulase activities fell and the brightness of the peroxidase and polyphenol oxidase bands gradually decreased, whereas the respiration intensity and the band count of esterase and peroxidase remained constant. After 60 days, the cultivated characteristics of the immobilized spawn were same as the fresh conventional solid cottonseed hull spawn. The results showed that immobilized spawn on the basis of the mycelial pellets of liquid spawn adsorbed in carrier can be used to extend the storage time and simplify transportation of liquid spawn of edible mushroom.
Weiping Zhong, Zhoujun Zhu, Fen Ouyang, Qi Qiu, Xiaoming Fan and Deyi Yuan
The normal development of anthers and the formation of functional pollen are the prerequisites for successful pollination and fertilization. In this study, we observed dynamic changes in inflorescence and anther development in the chinquapin (Castanea henryi) using stereomicroscopy, light microscopy, and transmission electron microscopy. We found that cytokinesis during meiosis in microsporocytes was of the simultaneous type, and that the tetrads were mainly tetrahedral. Mature pollen grains contained two cells with three germ pores. The anther wall was of the basic type and composed of epidermis, endothecium, middle layers, and tapetum. Mature anthers had no middle layer and tapetum. The tapetum was of the glandular type. At the early microspore stage, a large number of starch granules appeared in the endothecium, which was deformed at the late microspore stage. Lipid droplets appeared in tapetum during the early microspore stage, and a few lipid droplets were still found during tapetum degeneration. The mature pollen accumulated a large amount of starch and lipids. These findings demonstrated that the anther wall provides nutrients and protection for pollen development. There is relatively stable correspondence between the external morphological characteristics of male flowers and internal structure of anther development.
Ravneet K. Sandhu, Nathan S. Boyd, Shaun Sharpe, Zhengfei Guan, Qi Qiu, Tianyuan Luo and Shinsuke Agehara
Strawberry growers face rising production costs combined with competition from foreign imports. Relay cropping vegetables with strawberries is a unique approach that can diversify income and reduce the risk associated with strawberry production. Planting vegetable transplants on the same bed before strawberry crop termination enables continued berry harvesting while the new vegetable transplants become established. Relay cropping techniques of strawberry with eggplants were evaluated during the 2016–17 and 2017–18 seasons in Balm, FL. The strawberry crop was planted in September, and eggplant was transplanted into the beds either as a sole crop or with strawberry plants. Two experiments were conducted to optimize the planting date of strawberries and the termination date of strawberries. The objective of the research was to examine the competitive relationship between strawberry and eggplant crops and to define the optimal planting date for the eggplant and termination date of strawberries to minimize the competitive interaction and maximize the yield of both crops. Strawberry yields were unaffected (P = 0.938) by relay cropping or by the planting date of the eggplant. Eggplants grown without strawberries had 27% to 32% higher yields (P = 0.004) compared with relay-cropped eggplants, and eggplant yield decreased with later planting dates (P < 0.001). A partial budget analysis showed that transplant dates of 4 and 18 Jan. for eggplants with strawberries resulted in increased profits of $7320 and $3461 per ha, respectively, over the baseline treatment of strawberries alone, but later planting dates resulted in an overall economic loss ($7800–$16,000/ha). Strawberry termination dates did not affect eggplant yields. In conclusion, relay cropping eggplants with strawberries resulted in no effect on strawberry yields, reduced eggplant yields, but increased overall profits when eggplant were transplanted in early to mid-January. Relay cropping of strawberries with eggplants in early February to early March is less profitable than a monocrop of strawberries.