Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Min Lu x
Clear All Modify Search

Rosa roxburghii Tratt (Rosaceae) of various organ surfaces are widely existing trichomes. Certain varieties have fruits that are thickly covered with macroscopic trichomes. R. roxburghii Tratt (RR) and R. roxburghii Tratt. f. esetosa Ku (RRE) are important commercial horticultural crops in China because of their nutritional and medicinal values. RRE is generally considered a smooth-fruit variant that arose from RR. Despite their economic importance, the morphological and anatomic features of organ trichomes have not been explored in detail for these two rose germplasms. In this research, we investigated the distribution, morphology, and structure of trichomes distributed on the stem, pedicel, fruit, sepal, and marginal lobule sepals (MLS) of RR as well as RRE. This was accomplished using scanning electron microscopy (SEM). There are various shapes of trichomes distributed on the surfaces of stems, pedicels, fruits, and sepals of the two germplasms. Binate prickles arose on the stem nodes in both germplasms, but acicular trichomes, papillary trichomes, and ribbon trichomes were present only on the surfaces of pedicels in RR. Likewise, flagelliform trichomes were present only on the surfaces of pedicels in RRE. Furthermore, a transection of stems shows that thorns in the two germplasms are composed of epidermis, meristematic layer, and parenchyma cells. The trichome epidermis and meristematic layer in stems of RR are composed of round cells, whereas RRE exhibits square cells in the same layers. Trichomes on the fruit of RR were macroscopic and of single flagelliform and acicular shape. RRE exhibited polymorphic trichomes of flagelliform, triangular, capitate glandular, and elliptic glandular shapes on the pericarp. On the surfaces of RR sepals, there are thick macroscopic acicular trichomes. In contrast, RRE sepals presented flagelliform trichomes and capitate glandular trichomes. It is interesting that no trichomes were found on the surfaces of the MLS in the two germplasms; however, stomata were densely packed on the MLS of RRE when compared with RR. For RR, the trichomes on both sepal and fruit are composed of an epidermis layer and parenchyma cells; however, the epidermis cells of sepal trichomes are polygon-shaped, in contrast to the round epidermis cells in fruit. These results suggest that the two rose germplasms are good candidates for understanding the trichome ontogeny in the genus and for further breeding of the smooth organ trait in this rose species.

Free access

Plants with the flower color phenotype of double-color flowers are very precious and attractive and can usually be regarded as valuable germplasm resources for studying and improving flower color. This paper summarizes the coloring mechanism of double-color flowers in plants from three aspects: the formation of double-color flowers, the physiological factors affecting the coloring difference of double-color flowers, and the molecular mechanism affecting the coloring difference of double-color flowers, to provide a theoretical reference for the in-depth study of the coloring mechanism and molecular breeding of double-color flowers in the future.

Open Access

Fresh fruit of longan (Dimocarpus longan Lour.) are susceptible to pericarp browning and aril breakdown. Aril breakdown in longan fruit is regarded as one of the most important factors reducing quality and shortening storage life of the fruit. To better understand the molecular mechanism of aril breakdown, the expression patterns of three expansin (EXP) and three xyloglucan endotransglucosylase (XET) genes in relation to the aril breakdown of longan fruit stored at room temperature (25 °C) or low temperature (4 °C) were investigated. The results showed that aril breakdown index increased progressively during storage at 25 and at 4 °C. Northern blotting analysis revealed that the accumulations of three EXP and three XET genes exhibited differential characteristics with the occurrence of aril breakdown. During storage at 25 °C, the accumulations of Dl-XET3 increased after 1 day, suggesting that Dl-XET3 correlated well with the early aril breakdown, while Dl-EXP3 together with Dl-XET1 and Dl-XET2 was involved in later aril breakdown. However, expression of Dl-XET1 and Dl-XET2 could be mainly involved in aril breakdown of longan fruit stored at 4 °C. In addition, Dl-EXP2, whose accumulation increased sharply when longan fruit were transferred from low temperature to room temperature within 12 hours, was related to the aril breakdown in this storage period. These data indicated that Dl-EXPs and Dl-XETs were closely related to aril breakdown in longan fruit.

Free access

Albino tea plants are mutants that grow albino young leaves owing to lack of chlorophylls under certain environmental conditions. There are two types of albino tea plants grown in production, i.e., light- and temperature-sensitive albino tea cultivars. The former grows albino leaves in yellow color under intensive sunlight conditions and the later grows albino leaves with white mesophyll and greenish vein as the environmental temperature is below 20 °C. Both albino teas attract great attention because of their high levels of amino acids and the “umami” taste. There have been many studies focusing on the temperature-sensitive albino tea plants, whereas little attention has been given to the light-sensitive albino tea cultivars. The characteristics of the albino tea cultivars and the mechanism underlying them were reviewed in the present article based on the published literatures, including chemical compositions, morphological characteristics, and molecular genetic mechanism.

Free access