a) The new fertilizer causes faster growth in both varieties than other fertilizers
Answers
Answer:
npk
Explanation:
these are essentially nutrients
Answer:
Loquat (Eriobotrya japonica (Thunb.) Lindl., Maloideae, Rosaceae) is indigenous to China and represents one of the most important fruit species in subtropical areas of China1. Traditionally, there are several problems existed that limiting the propagation of loquat varieties, one is that seed reproduction takes too long juvenescent phase and seedling progeny cannot maintain variety characteristics due to genetic variation2, another problem is that explants are prone to browning in loquat asexual propagation system due to the higher content of phenols as compared with other Rosaceae fruit trees, therefore, callus proliferation needs strict selection of explants and proper medium. For example, Zhang3 reported that in tissue culture of loquat, leaf explants collected 5 days after bud sprouting were prone to severe browning and the highest mortality rate, whereas 10-day-old leaf explants showed minor browning symptoms and rapidly induced large quantity of granular light-green tight, high quality calluses, 15-day-old leaf explants also showed minor browning symptoms, but the generated calluses were yellow and loose, with lower proliferation efficiency. What is more, different varieties and ploidy materials of loquat have different requirements on medium formulation, especially hormone concentration and composition4, the asexual propagation system suitable for one loquat variety can not be directly copied and extended to other varieties, most importantly, even if asexual plant regeneration is successful, it will take another 7–8 years to grow into adult fruit trees. Therefore, grafting is still one of the most important methods for the expansion of varieties nowadays. Generally, under field conditions, fruit setting can start in the third year after grafting, rootstocks need to grow for approximately 2–3 years before they can be used for grafting, which greatly limits the breeding efficiency of loquat. However, the importance of fast-growing cultivation techniques of loquat rootstocks has not been paid enough attention.
The diameter of main stem is the primary factor to measure the growth and quality of rootstock5,6. Besides, it was reported in apple6,7 and citrus8 that growing indicators such as plant height, crown width, branch number, leaf number per plant, and the leaf area index of Idesia were significantly positively correlated with stem diameter of rootstocks. However, there was also contrary opinion that rootstocks that were too thick might slow the graft unions healing and reduce the survival rate of grafting8. In addition, a third view suggested that grafting survival rate and scion growth may be related to the maturity of rootstocks9. All of these views indicated that not only the stem diameter, but also the lignification degree of rootstock can affect rootstock quality.
Fertilization plays an important role in promoting the initial growth and improving the quality of rootstock10,11, for example, Silva12 found that superphosphate promoted the height and stem diameter of plants to the greatest extent after 30 d of transplanting. Ciriello13 reported that a there was a trend of increase in plant height and leaf area with addition of nitrogen (N), while the stem diameter and root dry mass data showed a negatively linear way. Tomislav14 reported that application of organic fertilizer can increase the content of total nitrogen (TN) and available phosphorus (AP) in the plowing layer soil and promote the root development of grape. All of these results suggested that optimum form, content and proportion of nutrient elements might play a crucial role in regulating soil state and improve plant growth. However, little information is available on the effects of different formulas of fertilizer on the initial growth of rootstock seedlings, reports on the relationships between fertilizer applications and the stem lignification process and the root morphogenesis are also rare. The objective of this study is to find out the optimal fertilization formula which can maintain the most vigorous growth as well as the most suitable lignification process, to provide a guidance for the rapid-growing cultivation technology .