6-Benzyladenine (6-BA) is a safe and efficient cytokinin. The adult tea plants of the cv. Longjing 43 were used in this study. The foliar portion of tea bushes were sprayed with different concentrations (50, 100, 200, or 400 mg·L−1) of 6-BA after heavy pruning, when three to four leaves grew out in late May. The effects of 6-BA application on the growth of the new shoots and lateral branches were quantified. After 5 months, treatments with 50, 100, 200, or 400 mg·L−1 6-BA suppressed plant height by 11.0%, 18.0%, 21.0%, or 22.0%, respectively; 6-BA at 100, 200, or 400 mg·L−1 decreased the number of lateral branches by 20.0%, 23.0%, or 18.0%, respectively. Meanwhile, treatments with 50, 200, or 400 mg·L−1 6-BA increased the length of lateral branches by 38.0%, 79.0%, or 81.0% respectively; 200 mg·L−1 6-BA increased the diameter of lateral branches by 8.0%. In addition, after 2 months, 50 or 200 mg·L−1 6-BA did not significantly affect the growth of functional leaves, 50, 100, or 200 mg·L−1 6-BA did not significantly affect photosynthetic rate (Pn) as compared with the control. Furthermore, 200 or 400 mg·L−1 6-BA significantly increased spring tea yield by 28.9% or 13.3%, respectively as compared with the control. In conclusion, 6-BA at the four concentrations promoted dwarfing and the formation of productive lateral branches and increased the spring yield, and 200 mg·L−1 6-BA exerted the best comprehensive effect.
Liping Zhang, Chen Shen, Jipeng Wei and Wenyan Han
Bo Zhang, Xue-Ren Yin, Ji-Yuan Shen, Kun-Song Chen and Ian B. Ferguson
The relationship between lipoxygenase (LOX) pathway-derived volatiles and LOX gene expression was evaluated in kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa cv. Bruno] during postharvest ripening at 20 °C. The C6 aldehydes n-hexanal and (E)-2-hexenal were abundant in peel compared with flesh tissue and declined as kiwifruit ripened. Esters such as ethyl butanoate and methyl butanoate were lower in the peel than flesh and accumulated when the fruit underwent a climacteric rise in ethylene production. Total LOX activity was higher in the peel than in the flesh and increased as kiwifruit ripened. Expression of AdLox2, AdLox3, AdLox4 and AdLox6 was high in the peel, whereas AdLox1 and AdLox5 showed similar levels in the peel and flesh at the ethylene climacteric. AdLox1 and AdLox5 transcript levels increased and AdLox2, AdLox3, AdLox4 and AdLox6 levels decreased during postharvest fruit ripening. Principal component analysis showed that n-hexanal and (E)-2-hexenal were grouped with LOX genes that were downregulated as kiwifruit ripened. The possible roles of LOX genes in relation to kiwifruit volatile formation during fruit ripening are discussed.
Li-Qiang Tan, Xin-Yu Wang, Hui Li, Guan-Qun Liu, Yao Zou, Shen-Xiang Chen, Ping-Wu Li and Qian Tang
Landrace tea populations are important recourses for germplasm conservation and selection of elite tea clone cultivars. To understand their genetic diversity and use them effectively for breeding, two traditional landrace tea populations, Beichuan Taizicha (BCTZ) and Nanjiang Dayecha (NJDY), localized to northern Sichuan, were evaluated for morphological characters, simple sequence repeat (SSR)–based DNA markers and the contents of biochemical components. A wide range of morphological variation and a moderately high level of DNA polymorphism were observed from both BCTZ and NJDY. NJDY had on average, bigger leaves, larger flowers, higher total catechins (TCs), and greater gene diversity (GD) than BCTZ. Interestingly, samples from BCTZ had a wide range in the ratio of galloylated catechins to nongalloylated catechins (G/NG) (1.83–8.12, cv = 48.8%), whereas samples from NJDY were more variable in total amino acid (TAA) content (25.3–50.8 mg·g−1 dry weight) than those from BCTZ. We concluded that the two Camellia sinensis landrace populations are of great interest for both individual selection breeding and scientific studies.
Arthur A. Schaffer, Marina Petreikov, Daphne Miron, Miriam Fogelman, Moshe Spiegelman, Zecharia Bnei-Moshe, Shmuel Shen, David Granot, Rivka Hadas, Nir Dai, Moshe Bar, Michael Friedman, Meir Pilowsky, Nehama Gilboa and Leah Chen
The carbohydrate economy of developing tomato fruit is determined by wholeplant source–sink relationships. However, the fate of the imported photoassimilate partitioned to the fruit sink is controlled by the carbohydrate metabolism of the fruit tissue. Within the Lycopersicon spp. there exists a broad range of genetic variability for fruit carbohydrate metabolism, such as sucrose accumulation and modified ratios of fructose to glucose in the mature fruit and increased starch synthesis in the immature fruit. Metabolic pathways of carbohydrate metabolism in tomatoes, as well as natural genetic variation in the metabolic pathways, will be described. The impact of sink carbohydrate metabolism on fruit non-structural carbohydrate economy will be discussed.