Iron is a trace element essential for normal plant life activities and is involved in various metabolic pathways such as chlorophyll synthesis, photosynthesis, and respiration. Although iron is highly abundant in the earth’s crust, the amount that can be absorbed and utilized by plants is very low. Therefore, plants have developed a series of systems for absorption, transport, and utilization in the course of long-term evolution. This review focuses on the findings of current studies of the Fe2+ absorption mechanism I, Fe3+ chelate absorption mechanism II and plant-microbial interaction iron absorption mechanism, particularly effective measures for artificially regulating plant iron absorption and transportation to promote plant growth and development. According to the available literature, the beneficial effects of using microbial fertilizers as iron fertilizers are promising but further evidence of the interaction mechanism between microorganisms and plants is required.

The aim of this study was to reveal the decomposition dynamics of kiwifruit litter and verify the variety differences and provide a scientific basis for rational fertilization in orchard. Kiwifruit litters of two varieties (‘Hongyang’ and ‘Jinyan’) were taken as the objects; the litter decomposition rate, the dynamics of macro-elements and micro-elements, and soil enzyme activities during the decomposition process were analyzed. The results showed that the litter decomposition rate of ‘Hongyang’ kiwifruit was faster than that of ‘Jinyan’ kiwifruit, because of the higher initial N and P content in the litter of the ‘Hongyang’ kiwifruit. The dynamic trends of macro-elements and micro-elements during litter decomposition of two varieties were similar. The C content was relatively stable, the P content was fluctuant, and the K content was decreasing. The contents of N, Fe, Mn, Cu, and Zn were increasing. The contents of Ca, Mg, and B increased first and then decreased. After 180 days of the decomposition experiment, more than 75% of the initial contents of C, N, P, K, Ca, Mg, and B were released. The dynamic trends of the soil enzyme activities of two varieties were generally similar. Due to the slow decomposition rate, the dynamic trends of soil enzyme activities of ‘Jinyan’ kiwifruit litter each showed hysteresis. The contents of Ca, Mg, and Mn were significantly correlated with some soil enzyme activities. In conclusion, the litter substrate quality of the two kiwifruit varieties is different, which leads to the difference in the decomposition rate. The litter decomposition of kiwifruit is an important supplement to the macro-element in orchard soil.

Lupinus polyphyllus is rich in color, making it a well-known horticultural ornamental plant. However, little is known about the genes related to anthocyanin and carotenoid biosynthesis in L. polyphyllus. In this study, transcriptome sequencing was performed on eight different colors of L. polyphyllus. A total of 1.13 billion clean reads were obtained and assembled into 89,124 unigenes, which were then aligned with six databases, resulting in the identification of 54,823 annotated unigenes. Among these unigenes, 76 and 101 were involved in the biosynthetic pathway of carotenoids and anthocyanins, respectively. In addition, 505 transcription factors were revealed, which belonged to the MYB, R2R3-MYB, NAC, bHLH, and WD40 families. A total of 6,700 differentially expressed genes (DEGs) were obtained by comparative transcriptome analysis. Among them, 17 candidate unigenes (four carotenoid genes, seven anthocyanin genes, and six TFs) were specifically up-regulated for one or more colors of L. polyphyllus. Eight representative candidate unigenes were analyzed by qRT-PCR. The findings enrich the transcriptome database of lupine, and provide a rich molecular resource for research on the coloration mechanism of L. polyphyllus.